SANAA, Yemen — Doctors from the scene of violent anti-government protests in Yemen’s capital Tuesday night said that what was originally thought to be tear gas fired by government forces on demonstrators might instead have been a form of nerve gas, which is forbidden under international law. 
 
 Military personnel opened fire and used what was originally assumed to be tear gas to disperse a group of demonstrators who were trying to bring additional tents into the protest area outside Sanaa University. 
 
 According to witnesses, the soldiers fired warning shots into the air before shooting gas — and in some cases live bullets — into the crowd, killing one and injuring at least 50. 
 
 Earlier reports indicated that the gas used was tear gas, but doctors who have been treating the wounded refuted that claim today. 
 
 “The material in this gas makes people convulse for hours. It paralyzes them. They couldn’t move at all. We tried to give them oxygen but it didn’t work,” said Amaar Nujaim, a field doctor who works for Islamic Relief. 
 
 “We are seeing symptoms in the patient’s nerves, not in their respiratory systems. I’m 90 percent sure its nerve gas and not tear gas that was used,” said Sami Zaid, a doctor at the Science and Technology Hospital in Sanaa. 
 
 Mohammad Al-Sheikh, a pathologist at the same hospital, said that some of the victims had lost their muscular control and were forced to wear diapers. 
 
 “We have never seen tear gas cause these symptoms. We fear it may be a dangerous gas that is internationally forbidden,” Al-Sheikh said. 
 
 One of the protest organizers, Rabie Al-Zuraiqi, 23, said he was struck by rubber bullets and gas during the attack. 
 
 “They say it’s tear gas, though it’s not. I can’t move my body. I went into a coma for more than four hours and I can’t see well now. I also have internal bleeding after being exposed to the gas,” he told GlobalPost. 
 
 Whether or not an illegal substance was used to gas protesters, Tuesday’s violence marked what appears to be a turning point for the country’s protest movement, which has dragged on for months. 
 
 Although there had been previous instances of violence, it had always been between plainclothed government supporters and anti-government protesters. The attack Tuesday was the first by uniformed police. 
 
 It was also the first time that live ammunition was used. Al-Zuraiqi said that a 30-year-old protester had died of internal bleeding after being shot in the back of the head. 
 
 In a makeshift hospital at the grounds of a mosque next to the university, volunteer doctors administered IV drips and treated bullet wounds on Tuesday night. 
 
 A surgeon probed a leg wound with forceps, while the man screamed, pulling out a fragment of metal. 
 
 "See this?" the doctor said, holding it up. "Do you see this? They are shooting people with live rounds." Another volunteer brought over a handful of empty shell casings. 
 
 In a corner of the mosque, a younger man screamed as a doctor poured coca-cola over his face to ease the pain from the gas. 
 
 After opening his eyes, the young man, Majid Al-Awaj, a protester from the northern province of Hajja, said the attack would only increase the strength of the revolt. 
 
 “We demand that Saleh be tried by the International Criminal Court,” Al-Awaj said. 
 
 At the university on Wednesday morning, protesters cleaned up from the previous night. A woman, crying, searched for her son, who she had sent to take food to the protesters but had never returned. 
 
 There have been daily anti-government demonstrations in Sanaa and other cities around the country since Egyptian President Hosni Mubarak's ouster on Feb. 11. During the past few weeks, 29 people have been killed in the unrest, according to international human rights groups. 
 
 President Ali Abdullah Saleh has said he will step down when his term ends in 2013 but has vowed to defend his government "with every drop of blood." 
 
 Watch video taken the night of the attack: ||||| Thousands of Yemenis defiantly demonstrated Wednesday at a public square, a day after the army stormed Sanaa University, firing live ammunition, killing one person and wounding scores of others. 
 
 A female anti-government protestor masked with her national flag listens to speeches during a demonstration demanding the resignation of Yemeni President Ali Abdullah Saleh, in Sanaa, Yemen, Tuesday,... (Associated Press) 
 
 Female anti-government protestors gesture during a demonstration demanding the resignation of Yemeni President Ali Abdullah Saleh, in Sanaa, Yemen, Tuesday, March 8, 2011. A Yemeni security official says... (Associated Press) 
 
 Anti-government protestors react during a demonstration demanding the resignation of Yemeni President Ali Abdullah Saleh, in Sanaa, Yemen, Tuesday, March 8, 2011. A Yemeni security official says about... (Associated Press) 
 
 A female anti-government protestor wearing a headband that reads in Arabic, " Leave", looks on during a demonstration demanding the resignation of Yemeni President Ali Abdullah Saleh, in Sanaa, Yemen,... (Associated Press) 
 
 An anti-government protestor reacts during a demonstration demanding the resignation of Yemeni President Ali Abdullah Saleh, in Sanaa, Yemen, Tuesday, March 8, 2011. A Yemeni security official says about... (Associated Press) 
 
 An anti-government protestor flashes the victory sign during a demonstration demanding the resignation of Yemeni President Ali Abdullah Saleh, in Sanaa, Yemen, Tuesday, March 8, 2011. A Yemeni security... (Associated Press) 
 
 Female anti-government protestors attend a demonstration demanding the resignation of Yemeni President Ali Abdullah Saleh, in Sanaa, Yemen, Tuesday, March 8, 2011. A Yemeni security official says about... (Associated Press) 
 
 Yemeni children look on while standing by a grocery store decorated with posters showing Yemeni President Ali Abdullah Saleh, in an alley of the old city of Sanaa, Yemen, Tuesday, March 8, 2011. A Yemeni... (Associated Press) 
 
 Anti-government protestors wave their national flag and chant slogans during a demonstration demanding the resignation of Yemeni President Ali Abdullah Saleh, in Sanaa, Yemen, Tuesday, March 8, 2011.... (Associated Press) 
 
 With a poster showing Yemeni President Ali Abdullah Saleh, right, Mohammed Ali, 88, who sells used clothes sits in front of his shop waiting for customers, in an alley of the old city of Sanaa, Yemen,... (Associated Press) 
 
 Female anti-government protestor attend a demonstration demanding the resignation of Yemeni President Ali Abdullah Saleh, in Sanaa, Yemen, Tuesday, March 8, 2011. A Yemeni security official says about... (Associated Press) 
 
 The attack escalated tensions in Yemen, which has been rocked by weeks of protests against President Ali Abdullah Saleh, a key U.S. ally in the campaign against al-Qaida who has been in power 32 years. 
 
 Abdullah al-Jeifi, 24, died and several other protesters who were shot in Tuesday's raid were in serious condition, said Mohammed al-Abahi, one of the doctors volunteering at the Sanaa University campus. Soldiers also used rubber bullets and tear gas in their assault. 
 
 Outraged at the government raid, more protesters camped out in tents near the university and on campus Wednesday. A group of young protesters issued a "black list" with the names of 13 officials they say are responsible for the violence against peaceful protesters. The names include the son of President Ali Abdullah Saleh who heads the Republican Guards, the interior minister and other top security officials. 
 
 The statement vowed revenge against those they called "criminals" and pledged to continue with the sit-in until they topple the regime. Thousands of people also protested in the southern port city of Aden and on the streets of Ibb province. 
 
 Human rights groups and the U.S. criticized Yemen's crackdown on protests Wednesday. 
 
 In Washington, State Department spokesman Mark Toner called on both sides to show restraint. "We urge the government of Yemen to investigate and hold accountable those who appear to have utilized excessive force," he said. 
 
 "These disturbing heavy-handed tactics used with lethal effect against protesters must stop immediately. People must be allowed to assemble and protest in peace," said Philip Luther, Amnesty International's deputy director for the Middle East and North Africa. 
 
 Human Rights Watch also issued a report, saying Yemeni security forces killed at least nine people and injured 150, some of them children, during peaceful protests in the southern city of Aden last month. 
 
 "Shooting into crowds is no way to respond to peaceful protests," said Joe Stork, deputy Middle East and North Africa director at Human Rights Watch. 
 
 Yemen's Interior Minister, Gen. Mouthar al-Masri, told reporters Wednesday night that gunfire from the rooftop of a building near the university led to the clashes. 
 
 Students at Sanaa University have been sleeping on campus since mid-February, shortly after the start of the protests calling on Saleh to step down. In an escalation, soldiers stormed the campus late on Tuesday, shooting live ammunition, rubber bullets and firing tear gas. About 90 protesters sustained gas inhalation and minor injuries in the raid. 
 
 "This aggression is an indication that the regime is collapsing and cannot stand before the youth revolution," said Mohammad Qahtan, a spokesman for the opposition. 
 
 Witnesses said the mayor of Sanaa, Abdul-Rahman al-Akwa, who is also the brother-in-law of Saleh, led a group involved in the raid. 
 
 Medical officials said at least two of the wounded were in serious condition. Rabih al-Zuraqi, 25, was suffering from brain hemorrhage while 18-year-old Jamal al-Buhaisi suffered complications from a bullet wound to the shoulder. A few others had breathing problems due to smoke inhalation. 
 
 Hosni al-Jushai, a doctor at the Science and Technology Hospital who was volunteering with the protesters, said it appeared from the symptoms that security forces used banned nerve gas against the demonstrators, in addition to tear gas. 
 
 In a separate incident Wednesday, bodyguards of lawmaker Mohammad Abdel Illah al-Qadi exchanged fire with a security patrol in Sanaa. Al-Qadi's brother and a bodyguard were wounded. 
 
 Al-Qadi, a longtime stalwart of Saleh's regime, said he was resigning from the ruling party last month and joining the opposition. 
 
 It was not clear what triggered the clash. 
 
 Even before Yemen was hit by the wave of protests, the country was growing increasingly chaotic with a resurgent al-Qaida, a separatist movement in the south and an off-on Shiite rebellion in the north vexing the government. 
 
 In an attempt to quell escalating protests, the president called for national dialogue after meetings Monday with the country's political and security chiefs. The state-run news agency said the conference would be held Thursday and would include thousands of representatives from across Yemen's political spectrum. 
 
 But opposition leader Yassin Said Numan said there would be no dialogue unless Saleh agreed to step down by year's end. 
 
 Saleh's pledge not to run for re-election in 2013 has failed to defuse the protests, as have his calls for a unity government with opposition figures.
– Doctors and protesters in Yemen think the government is using banned nerve gas, not regular tear gas, to quell protests, reports Global Post. Three doctors treating patients say the symptoms are suspiciously severe. “The material in this gas makes people convulse for hours," said one field doctor after soldiers fired bullets and gas into a crowd of protesters outside Sanaa University yesterday. "We are seeing symptoms in the patient’s nerves, not in their respiratory systems," said another. "I’m 90% sure it's nerve gas and not tear gas." If so, it would put Yemen authorities in violation of international law. Either way, the government seems to be taking an increasingly violent approach, notes Global Post. In addition to the gas, soldiers fired live ammunition, killing one protester. Demonstrations continued today, notes AP.