Myanmar activists planned more anti-coup rallies on Monday, a day after dozens of protesters were killed in clashes with security forces and unidentified assailants torched several Chinese-financed factories in the commercial hub of Yangon.

The attacks on businesses from China provoked its strongest comments yet on the turmoil gripping its Southeast Asian neighbour, where many people see China as supportive of the Feb. 1 coup.

The Chinese embassy said many Chinese staff were injured and trapped in the arson attacks, and urged Myanmar’s ruling generals to stop violence and ensure the safety of people and property.

Japan, which has long competed for influence in Myanmar with China, said it was monitoring the situation and considering how to respond in terms of economic cooperation.

The worst of Sunday’s bloodshed came in the Yangon suburb of Hlaingthaya where security forces killed at least 34 protesters after arson attacks on Chinese-owned factories, the Myanmar Now media group said. A doctor in the area put the death toll there at 33 in a Facebook message.

Sixteen people were killed in other places, rights group Assistance Association for Political Prisoners (AAPP) said, as well as one policeman, making it the bloodiest day since the coup.

State media said martial law had been imposed in Hlaingthaya and several other districts of Yangon.

The latest deaths bring the toll from the protests to 138, based on a tally by the AAPP.

“The horrific increase in the number of protesters killed by live fire over the weekend shows just how emboldened Myanmar’s security forces are to target protesters with live ammunition,” Phil Robertson, deputy Asia director of Human Rights Watch said in a statement.

A junta spokesman did not answer calls requesting comment.

The army said it took power after its accusations of fraud in a Nov. 8 election won by veteran democracy leader Aung San Suu Kyi’s party were rejected by the electoral commission. It has promised to hold a new election, but has not set a date.

Suu Kyi has been detained since the coup and is due to return to court on Monday. She faces at least four charges, including the illegal use of walkie-talkie radios and infringing coronavirus protocols.

The Hlaingthaya industrial suburb is home to migrants from across Myanmar. On Sunday, security forces opened fire as black smoke billowed from factories.

“It was horrible. People were shot before my eyes. It will never leave my memory,” said one photojournalist on the scene who did not want to be named.

Army-run Myawadday television said security forces acted after four garment factories and a fertilizer plant were set ablaze and about 2,000 people had stopped fire engines from reaching them.

Violence also broke out in other parts of Yangon as protests ran late into Sunday night with several people killed, residents said.

Protests were planned for Monday in the second city of Mandalay, activist Myat Thu said, while residents in Yangon said demonstrations were planned in two areas of the city.

Mobile data appeared to be shut down nationwide.

‘STOP ALL VIOLENCE’

Western countries have condemned the violence and Asian neighbors have offered to help resolve the crisis but Myanmar has a long record of rejecting outside intervention.

Tom Andrews, the United Nations human rights investigator on Myanmar, appealed for U.N. member states to cut the supply of cash and weapons to the military.

“Heartbroken/outraged at news of the largest number of protesters murdered by Myanmar security forces in a single day. Junta leaders don’t belong in power, they belong behind bars,” he said on Twitter.

China’s embassy described the situation as “very severe” after the attacks on the Chinese-financed factories and it urged authorities to “stop all acts of violence, punish the perpetrators in accordance with the law and ensure the safety of life and property of Chinese companies and personnel”.

Anti-Chinese sentiment has risen since the coup, with opponents of the army takeover noting Beijing’s muted criticism compared with Western condemnation.

Protest leader Ei Thinzar Maung said investors should take heed of the torched factories.

“If you want to do business in Myanmar stably, then respect Myanmar people,” she said. “Fighting Hlaingthaya, we are proud of you!!”

A senior official from Suu Kyi’s National League for Democracy party, Mahn Win Khaing Than, who is on the run along with most senior party officials, said on the weekend the civilian government would give people the legal right to defend themselves. It announced a law to that effect on Sunday.