Opposition to Myanmar's new military regime intensified on Saturday as spontaneous neighbourhood watch groups mobilised to thwart arrests of anti-coup activists and the UN demanded the release of ousted leader Aung San Suu Kyi. The army takeover that brought a decade-old democracy to an end last week has unleashed a storm of anger and defiance, with huge daily protests bringing urban centres around the country to a standstill. Since taking Ms Suu Kyi and her top allies into custody, troops have stepped up arrests of civil servants, doctors and others joining strikes to call on the generals to relinquish power. Crowds defied overnight curfews to mass on the streets as night fell, hours after finishing a seventh straight day of rallies, following rumours that police were launching a fresh wave of arrests. One group swarmed a hospital in the city of Pathein after rumours that a popular local doctor would be taken, chanting a Buddhist prayer urging protection from harm. "If I have problems, I will ask for your help," Than Min Htut told the group who had come to aid him, flashing the three-finger salute that has come to symbolise resistance to the coup. The doctor said on Saturday that he was still free and would continue participating in a civil disobedience campaign opposing military rule. People in Yangon skirted a junta ban on Facebook to organise neighbourhood watch groups that warned of rumoured arrests. "We didn't know who will be taken, but when we heard the sound, we went out to join our neighbours," said Tin Zar, a storekeeper in Yangon's north. "Even if they shoot, we are not afraid," she said. More than 320 people have been arrested since last week's coup, according to the Assistance Association for Political Prisoners monitoring group. An emergency session of the UN Human Rights Council in Geneva called for the new regime to release all "arbitrarily detained" persons and hand power back to Ms Suu Kyi's administration. The UN deputy rights chief Nada Al Nashif warned Myanmar in the Friday meeting that "the world is watching" events unfold in the country. News of more arrests did not stop tens of thousands from returning to the streets of Yangon on Saturday, where columns of traffic ground to a halt and blared their horns for five minutes to mark the birthday of Aung San, Ms Suu Kyi's father. The independence hero is revered for freeing the country from colonial control but was gunned down at the age of 32, just months before the end of British rule in 1947. Nationwide protests have remained largely peaceful, though authorities have used tear gas, water cannon and rubber bullets to disperse some rallies. At least two people in the capital Naypyidaw were shot by police and critically injured, including one 20-year-old woman who remains in intensive care. Officers fired rubber bullets wile clearing a sit-in protest in the port city of Mawlamyine on Friday, injuring several demonstrators. Nine others taken into custody were later freed after a crowd mobbed a police station and demanded their release. State media reported counter-protests by military supporters in various parts of the country on Friday, citing crowd estimates a small fraction of the anti-coup rallies seen in the past week. A demonstration in Naung Po Aung on the same day underscored the nationwide breadth of opposition to the junta, with hundreds marching in procession through the village of only 7,500 people in one of the most remote corners of the country. So far, the generals remain undeterred by the widespread condemnation on the streets and from abroad. They justified seizing power with claims of widespread voter fraud in November's general election, which Ms Suu Kyi's National League for Democracy (NLD) won in a landslide. Washington this week imposed targeted sanctions against top military brass. But traditional allies of the country's armed forces, including Russia and China, have criticised the international outcry against the coup as interference in Myanmar's internal affairs. Ms Suu Kyi, 75, has not been seen since her detention nearly two weeks ago. A NLD official, Kyi Toe, said on Saturday that she was in Naypyidaw and still in "good health".