The police in Myanmar opened fire on protesters in the city of Mandalay on Saturday, killing two and injuring at least 10, witnesses said.

The shootings occurred as the authorities were trying to force workers back to their jobs at a local shipyard. They were among hundreds of thousands of laborers across Myanmar who have walked off their jobs to protest the military’s Feb. 1 coup and its ouster of elected civilian leaders.

More than 1,000 demonstrators gathered at the shipyard to block the police, leading to a tense standoff that lasted much of Saturday afternoon. The authorities used water cannons, rubber bullets, tear gas, slingshots and ultimately live ammunition to break up the crowd, witnesses said.

The shootings came one day after the death of another protester, a 20-year-old woman whom the police shot in the head at a demonstration in the capital, Naypyidaw, on Feb. 9. The woman, who was on life support before succumbing to her injury, is believed to have been the first person killed in the protests against the coup.