Security forces killed at least 14 protesters in a poor, industrial suburb of Myanmar's main city on Sunday and at least three people in other parts of the country, according to local media, APA reports quoting Reuters.
State television said a policeman had also been killed in one of the bloodiest days of protests against the Feb. 1 coup.
China's embassy called on Myanmar to protect its property and citizens after saying two Chinese-financed garment factories were set ablaze by unknown attackers.
Protests are now in their sixth week since the coup toppled elected leader Aung San Suu Kyi and plunged the Southeast Asian country into turmoil, with the economy paralysed by strikes by opponents of the army takeover.
Security forces opened fire on protesters in the Hlaingthaya district of the city, a poor suburb that is home to migrants from across the country, domestic media said. Plumes of black smoke rose over the area.
Myanmar Now said at least 14 protesters had been killed, according to the local hospital and a rescue worker.