( CNN ) -- Syrian security forces flooded the restive cities of Daraa and Latakia on Monday , patrolling the streets , protecting government buildings and in at least one case clashing with protesters , according to witnesses . Both cities have been the scene of violent clashes between protesters and security forces in recent days , with at least 37 deaths since last week , according to the U.N. Office of the High Commissioner for Human Rights . In Daraa on Monday , forces filed into the city 's main square before dawn , tearing down the tents and anti-government signs of about 100 protesters who were staying there overnight , according to one eyewitness . The forces fired shots into the air and turned water cannons on the protesters , the witness said , leading to a clash with hundreds of nearby residents who rushed to the square to defend the demonstrators . The resulting confrontation lasted about 30 minutes , reportedly without injuries or arrests , according to the witness . Another witness said the army was blocking the city on three sides and that security forces , surrounding government buildings and the Al-Omari mosque where some protesters remained , had opened fire . The witness was not aware of any injuries . Syria 's state-run news agency said the government denied firing on protesters , calling the allegations `` completely false . '' Political dissident Aman Aswad , who is in Daraa , said the city is extremely tense . `` People are sitting at home scared , watching the updates on TV , '' he said . In Latakia , another eyewitness said mysterious men in black shirts carrying sophisticated weapons terrorized residents overnight , firing into the air and banging on the doors of homes . `` We do not understand who these men are but government officials say they are members of a 'foreign group , ' '' the witness said . `` We all think they are lying about this because every time one of them is captured and handed over to the police he is released . '' Hundreds of government troops have also filtered into the Latakia and are guarding public buildings and other important sites , the witness said . CNN could not independently confirm the accounts because the Syrian government has yet to grant access to the network . Syria is the latest in a string of Arabic-speaking nations beset with discontent over economic and human rights issues . Syria 's discontent is centered Daraa , a southern city in the impoverished country 's agricultural region , where security forces and anti-government protesters have sporadically clashed for nearly two weeks . Thousands of protesters marched Friday to the governor 's building in Daraa , where they burned pictures of President Bashar al-Assad and toppled a statue of his father , the late President Hafez al-Assad , according to a witness who identified himself only as Adbullah . Aswad , a political dissident , said dozens of people appeared to have been killed or wounded in clashes with security forces during those protests . In Latakia , government blamed `` armed gangs '' who seized police weapons on the violence last week that led to the deaths there of 10 security force members and civilians and two gunmen , according to the Syrian state-run news agency , SANA . The agency reported that 200 people , most of them security forces , were wounded by the gangs . U.S. Secretary of State Hillary Clinton criticized Syria 's government over the violence on the CBS Sunday morning news show `` Face the Nation . '' `` Certainly we deplore the violence in Syria , '' she said . `` We call as we have on all of these governments during this period of the Arab awakening , as some have called it , to be responding to their people 's needs , not to engage in violence , permit peaceful protests and begin a process of economic and political reform . '' CNN 's Salma Abdelaziz contributed to this report .
NEW : Witness : " I was in the back of a car with my friend and we were driving down this road. NEW : Mysterious black-shirted men terrorize residents in Latakia , witness says . Daraa is extremely tense , according to a witness . U.N. : At least 37 people have died in clashes between protesters and security forces .