(Reuters) - Myanmar security forces cornered hundreds of young protesters overnight in a district of Yangon and threatened to hunt for them door to door as the United States and United Nations appealed for them to be allowed to leave. Thousands of people defied a night time curfew to take to the streets of Myanmar’s main city in support of the youths in the Sanchaung district, where they had been holding the latest daily protest against the Feb. 1 coup. The army takeover and arrest of elected leader Aung San Suu Kyi has plunged Myanmar into chaos. Security forces have killed over 60 protesters and detained more than 1,800 since then, an advocacy group said. In Sanchaung, police firing guns and using stun grenades announced they would check houses for anyone from outside the district and would punish anyone caught hiding them. U.N. Secretary-General Antonio Guterres “calls for maximum restraint and urges for the safe release of all without violence or arrests,” U.N. spokesman Stephane Dujarric said. The U.N. office in Myanmar as well as the U.S. and British embassies appealed to security forces to allow protesters to leave without violence or arrest. There was no sign of them withdrawing. On Facebook, residents and the local MTK news service posted that as of the early hours of Tuesday 20 people had been arrested in Sanchaung after police searched houses. Elsewhere in Yangon, thousands of people defied an 8 p.m. curfew, chanting “Free the students in Sanchaung”, prompting security forces to fire guns and use stun grenades to try to disperse them. A junta spokesman did not answer calls requesting comment. State television MRTV earlier said: “The government’s patience has run out and while trying to minimise casualties in stopping riots, most people seek complete stability (and) are calling for more effective measures against riots.” Three protesters were killed in demonstrations in northern Myanmar and the Irrawaddy Delta on Monday, according to witnesses and local media. DOORS BROKEN In the Lanmadaw district of Yangon, residents said security forces broke down doors in overnight arrest raids after youths there said they had caught some suspected soldiers transporting weapons in a private car. “Please help, my door is being broken,” one woman posted on Facebook. Twenty minutes later she said her father and uncle had been taken away. She did not know where. Demonstrations have been held daily for more than a month to demand the release of Suu Kyi and respect for the election her National League for Democracy (NLD) party won last November. The army took power citing fraud in the ballot - an accusation rejected by the electoral commission. It has promised another election, but without giving a date. The military has brushed off condemnation of its actions, as it has in past periods of army rule when outbreaks of protest were bloodily repressed. Slideshow ( 4 images ) This time it is also under pressure from a civil disobedience movement that has crippled government business and from strikes at banks, factories and shops that shut much of Yangon on Monday. In a diplomatic blow to the junta, Myanmar’s ambassador in Britain followed its U.N. representative in calling on Monday for the release of Suu Kyi - drawing praise from British foreign minister Dominic Raab. Britain, the United States and some other Western countries have imposed limited sanctions on the junta. The European Union is preparing to widen its sanctions to target army-run businesses, according to diplomats and two internal documents seen by Reuters. Slideshow ( 4 images ) Thailand’s state broadcaster PBS said areas had been set aside along the border with Myanmar to house any refugees fleeing the unrest.