Sanaa , Yemen ( CNN ) -- Hurling rocks and brandishing daggers and sticks , supporters of longtime President Ali Abdullah Saleh plunged into a crowd calling for his ouster in Sanaa on Friday as rising momentum in Yemen sprouted similar protests in other towns . Reports of excessive force prompted calls for restraint amid intensifying demonstrations . U.S. President Barack Obama voiced concern about what the U.S. Embassy in Yemen described as `` a disturbing rise in the number and violence of attacks against Yemeni citizens gathering peacefully to express their views on the current political situation . '' `` The United States condemns the use of violence by governments against peaceful protestors , '' Obama said . `` Wherever they are , people have certain universal rights , including the right of peaceful assembly . '' The embassy statement said `` the attacks are contrary to the commitments that President Saleh has made to protect the right of Yemeni citizens to gather peacefully to express their views . '' The violence in Yemen and Libya on Friday stood in sharp contrast to images from Cairo 's Tahrir Square , where Egyptians showed up en masse to celebrate the toppling of President Hosni Mubarak a week ago . Saleh 's foes in Yemen are trying to score their own victory . After midday prayers concluded , they marched from the gates of Sanaa University to the streets , where security forces and riot police tried to stay between rival demonstrators Friday . Some told Amnesty International that they had been surrounded by security forces , aided by `` thugs '' who fired shots at them and beat them . `` We are very scared , particularly because there are children with us , '' a protester told the human rights monitoring group . `` We 've tried to get the children out of the area , but the security forces have not allowed us to do so . '' `` After Mubarak , now it 's Ali 's turn , '' chanted the anti-government protesters . `` The people want the fall of the regime . '' `` I 'm out here today because we want the president to go and we want to make sure that he and his family do n't stay in power , '' said Khalid Amer , a student . Despite concessions from Saleh , a tide of anger is sweeping through Yemen 's youths , who say they are simply fed up with the status quo . At least 30 anti-government demonstrators were injured , according to Abdul Naser Al-Dumaini , an anti-government protester at a demonstration in Sanaa . The day before , at least 20 people were injured in Sanaa . Opposition lawmaker Ahmed Hashid said police at the scene did not try to intervene . In Taiz , more than 10,000 anti-government demonstrators , including 4,000 women , gathered Friday in Freedom Square in a seventh straight day of protests , witnesses said . An assailant drove by the square and hurled a grenade , killing one person , a police official said . At least 43 others were wounded . And in the coastal city of Aden , about 3,000 anti-government demonstrators gathered in the Al-Mansoura District , witnesses said . Five people have been killed in Aden since Wednesday , hospital and government officials said . Aref al-Qubati , a participant whose friend was one of the victims , said police fired to disperse protesters . The Committee to Protect Journalists reported that `` at least four photojournalists were attacked , beaten and had their cameras confiscated '' by government supporters at the protests . The government countered the coverage of discontent in Yemen by reporting on sympathetic demonstrations . The state-run Saba news agency said a million demonstrators had marched in Taiz , hoisting Yemeni flags and pictures of Saleh . And Deputy Interior Minister Hussein al-Zawa'ari blamed a southern secessionist movement for the unrest and deaths in Aden , Saba said . Saleh has called for an investigation into the Aden violence , and Vice President Abdu Rabo Mansour Hadi met with the governor Thursday , Saba said . Saleh , in power for 32 years , met earlier in the week with his National Defense Council to discuss discontent in his nation . The council `` stressed all should practice their rights according to the constitution , in a peaceful way and without violence , chaos , sabotage and lawbreaking , '' Saba said . Saleh has been in touch with King Hamad of Bahrain , which is also mired in unrest . `` He pointed out that there are schemes aimed at plunging the region into chaos and violence targeting the nation 's security and the stability of its countries , '' Saba said . `` Those who commit acts of disorder and vandalism ( are ) simply implementing suspicious foreign agendas ... '' The report did n't suggest who might be behind the agendas . In an attempt to quell growing discontent , Saleh , a U.S. ally in the fight against an offshoot of al Qaeda in Yemen , has announced he wo n't seek another term in 2013 . He also said he would postpone parliamentary elections scheduled for April to allow more time for discussions about reform . Yemen 's situation is compounded by the fight against al Qaeda , the southern separatist movement in its once-independent south , a Shiite uprising and a looming shortage of water .
NEW : Obama : U.S. condemns violence `` by governments against peaceful protestors '' Rival demonstrators clash at Sanaa University . Scores of injuries reported . Yemeni President Ali Abdullah Saleh has been in power for 32 years .