Bangkok , Thailand ( CNN ) -- Gunmen opened fire on peaceful protesters in Thailand Friday night , killing one and wounding three , national security chief Paradon Patthanathabut said . Police do not know who the gunmen are . Protesters had gathered in the government district of Bangkok this week to demand the ouster of the country 's prime minister and threatened to shut the city down for a month in January . Thailand 's army chief has called an urgent meeting of his senior staff for Friday to discuss the protests . The crowd gathered at the Democracy Monument and near the Government House , but had withdrawn from other sites where they had protested a day before , including the Thai-Japanese Sports Complex Stadium . In protests near that complex , one police officer died and scores of people were injured , according to police . U.S. Embassy warning . The U.S. Embassy in Bangkok issued an emergency notice urging caution near the site of protests . `` Even demonstrations that are meant to be peaceful can turn confrontational and escalate into violence . You should avoid areas of demonstrations , and exercise caution if in the vicinity of any large gatherings , protests , or demonstrations . Be alert and aware of your surroundings and pay attention to local news media reports , '' the embassy said . The unrest came as demonstrators hoped to force Prime Minister Yingluck Shinawatra from office . In a bid to cool tensions , the prime minister dissolved the nation 's parliament this month and called for new elections , to be held February 2 . But the move has done little to appease protesters , who remained on the streets . Thursday 's protests , in which nearly 2,000 anti-government demonstrators gathered at locations across the capital , turned violent . Police reported 129 people were injured , including the 25 police officers . A police spokesman had previously reported 35 officers had been injured , but some of the injured had been counted twice . Call to postpone elections . The national Election Commission urged the government to postpone elections . `` The current violence that just took place , it is something that we have already signaled to those who are responsible that it could happen , '' the commission said . `` We urge the government to postpone the election until a joint agreement from both sides is reached . '' But Deputy Prime Minister Pongthep Thepkarnchana said a delay was n't possible . `` The election can not be postponed as it is against the constitution . The reform process can be done simultaneously with coming elections , '' he said . Protest leaders have said they want to rid Thailand of the influence of former Prime Minister Thaksin Shinawatra , the older brother of Yingluck Shinawatra . That 's an ambitious goal in a country where every election since 2001 has been won by parties affiliated with Thaksin Shinawatra , a billionaire who built his political success on populist policies that appealed to Thailand 's rural heartland . Thaksin Shinawatra was ousted in a military coup in 2006 and has spent most of the time since then in exile overseas . If he returns , he risks a two-year prison sentence on a corruption conviction , which he says was politically motivated . The current protests in Bangkok were prompted by a botched attempt by Yingluck Shinawatra 's government to pass an amnesty bill that would have opened the door for her brother 's return . That move added fuel for critics who accuse her of being nothing more than her brother 's puppet , an allegation she has repeatedly denied . CNN 's Ed Payne contributed to this report .
Unidentified gunmen fired upon demonstrators . The government says the attack was carried out by a group of armed men who were trying to overthrow President Bashar al-Assad. The national Election Commission had called for a delay , citing the violence .