Police have fired on protesters in Myanmar killing at least 18, the UN human rights office says, on the deadliest day of anti-coup rallies. Deaths were reported in several cities including Yangon, Dawei and Mandalay as police used live rounds and tear gas. Security forces began the violent crackdown on Saturday, after weeks of largely peaceful protests against the 1 February military takeover. Government leaders, including Aung San Suu Kyi, were overthrown and detained. Social media footage from Sunday showed protesters running away as police charged at them, makeshift roadblocks being erected, and several people being led away covered in blood.