Thailand’s prime minister denied Tuesday that his country’s security forces forced villagers back to Myanmar who had fled from military airstrikes, saying they returned home on their own accord. Prime Minister Prayuth Chan-ocha, nevertheless, said his country is ready to shelter anyone who is escaping fighting, as it has done many times for decades. His comments came a day after humanitarian groups said Thailand has been sending back some of the thousands of people who have fled a series of air attacks by Myanmar's military. “There is no influx of refugees yet. We asked those who crossed to Thailand if they have any problem in their area. When they say no problem, we just asked them to return to their land first. We asked, we did not use any force,” Prayuth told reporters. “We won’t push them back,” he said. ’If they are having fighting, how can we do so? But if they don’t have any fighting at the moment, can they go back first?” The governor of Thailand's Mae Hong Son province, where as many as 3,000 refugees had sought shelter, said later that those still on Thai soil were expected to return to their own country in a day or two. The weekend attacks, which sent ethnic Karen people to seek safety in Thailand, were another escalation in the violent crackdown by Myanmar’s junta on protests against its Feb. 1 takeover. At least 510 protesters have been killed since the coup, according to Myanmar’s Assistance Association for Political Prisoners, which says the actual toll is likely much higher. It says 2,574 people have been detained. Protests continued Tuesday despite the deaths of more than 100 people on Saturday alone. Engineers, teachers and students from the technology university in the southern city of Dawei marched without incident. The number of protesters killed in the city rose to eight with the announcement of the death of a teenager who was shot by soldiers on Saturday as he rode a motorbike with two friends. According to local media, a hospital certificate attributed his death to “serious injuries as he fell from a motorbike.” Medical workers in Mandalay, the country’s second biggest city, honored three of their colleagues who have been killed by security forces. The two doctors and a nurse were remembered in a simple ceremony in front of a banner with their photographs and the words “Rest In Power.” At a cemetery in the biggest city, Yangon, three families gave their last farewells to relatives killed Monday in a night of chaos in the South Dagon neighborhood. Residents said police and soldiers moved through the streets firing randomly with live ammunition. The coup that ousted the government of Aung San Suu Kyi reversed the country's progress toward democracy since her National League for Democracy party won elections in 2015 after five decades of military rule. At Thailand’s Mae Sam Laep village along the Salween River, which forms the border with Myanmar, paramilitary Thai Rangers on Tuesday twice waved off a boat that had come from the other side carrying seven people, including one lying flat and another with a bandage on his head. But ambulances soon arrived on the Thai side and it landed anyway. Thai villagers helped medical staff carry the injured people on stretchers to a small clinic at a nearby checkpoint. One man had large bruises on his back with open wounds, an injury one medical staffer said could have been caused by an explosion. An elderly woman in the group had small cuts and scabs all over her face. Thai nurses in protective gear to guard against COVID-19 attended to her, giving her and others tests for the coronavirus. Another villager from the boat, 48-year-old Aye Ja Bi, said he had been wounded by a bomb dropped by a plane. His legs were hit by shrapnel and his ears were ringing, he said, but he was unable to travel to get help until Tuesday. The airstrikes appeared to be retaliation for an attack by guerrillas of the Karen National Liberation Army on a government military outpost, in which they claimed to have killed 10 soldiers and captured eight. The group is fighting for greater autonomy for the Karen people. About 2,500-3,000 refugees crossed into Thailand on Sunday, according to several humanitarian aid agencies who have long worked with the Karen. They said on Monday, however, that Thai soldiers had begun to force people to return to Myanmar. “They told them it was safe to go back even though it is not safe. They were afraid to go back but they had no choice,” said a spokesperson for the Karen Peace Support Network, a group of Karen civil society organizations in Myanmar. The army has restricted journalists’ access to the area where the villagers crossed the border. Myanmar’s government has battled Karen guerrillas on and off for years — along with other ethnic minorities seeking more autonomy — but the airstrikes marked a major escalation of violence. Political organizations representing the Karen and Kachin in northern Myanmar have issued statements in recent weeks warning the government against shooting protesters in their regions and threatening a response. They were joined Tuesday by the Three Brothers Alliance, which represent the guerrilla armies of the Rakhine, Kokang and Ta-ang -- also known as Palaung -- minorities. The alliance condemned the killing of protesters and said if it did not stop immediately, they would abandon a self-declared cease-fire and join with other groups to protect the people. Their statement, like those of the Karen and Kachin, seemed to suggest that any military response by them would be in their home areas, not in the cities of central Myanmar where the protests and repression have been the strongest. Supporters of the protest movement are hoping that the ethnic armed groups could help pressure the junta. Protest leaders in hiding say they have held talks, but there have been no commitments. The United States on Monday suspended a trade deal with Myanmar, also known as Burma, until a democratic government is restored in the Southeast Asian country. The office of the U.S. Trade Representative said the country was immediately suspending “all U.S. engagement with Burma under the 2013 Trade and Investment Framework Agreement.″ Under the agreement, the two countries cooperated on trade and investment issues in an effort to integrate Myanmar into the global economy, a reward for the military’s decision to allow a return to democracy — a transition that ended abruptly with last month’s coup. The announcement Monday doesn’t stop trade between the two countries. Last week, the United States restricted American dealings with two giant Myanmar military holding companies that dominate much of that country’s economy.