International refugee laws ban the return of people to countries where their lives may be in danger.
But refugees, aid groups and Thai officials themselves say Thailand still sends thousands of people who fled violence by Myanmar's military back home.
Since its takeover of the country last year, Myanmar's military has killed more than 1,700 people and arrested more than 13,000.
The military has also tortured children, women and men.
The refugees are now unsure of their future.
Many live on both sides of the river dividing the two countries, as fighting continues in Myanmar.
Hay is a young woman from Myanmar.
She and her family now live in the tall grasses near the river on the Thai border.
Like thousands of others, Hay left her village for neighboring Thailand after the military's takeover.
Returning to Myanmar would place her and her family at risk of death.
But that is what Thai officials tell them to do at least once a week, she told The Associated Press.
The Thai government does not want to hurt its relationship with Myanmar's ruling military.
"When they told us to go back, we cried and explained why we can't go back home," Hay said.
"Sometimes we cross back to the Myanmar side of the river. But I have not returned to the village at all."
Sally Thompson leads The Border Consortium, which provides aid to Myanmar refugees in Thailand.
"You can't keep going back and forth across the border," she said.
"You've got to be somewhere where it's stable… And there is absolutely no stability in Myanmar at the moment."
Thailand has not signed on to the United Nations Refugee Convention.
It claims Myanmar's refugees return home voluntarily.
Thailand also says it has followed international laws that say that people must not be returned to a country where they would face torture, punishment or harm.
"As the situation on the Myanmar side of the border improved," Thai officials helped citizens voluntarily return to Myanmar, said the spokesperson for Thailand's Ministry of Foreign Affairs.
Thousands of people from Myanmar have sought refuge in Tak province.
The governor there said many crossed illegally when there was no fighting.
"We had to send them back as the laws said," the governor said.
"When they faced the threats and crossed here, we never refused to help them."
The international refugee agency UNHCR says that 48,000 people have fled to neighboring countries since the Myanmar military's takeover.
The agency says Thai government sources estimate around 17,000 have sought safety in Thailand.
But the Thai-Myanmar Border Command Center reports that only around 2,000 are currently living in Thailand.
Those fleeing the fighting between the Myanmar military and ethnic minority groups must wade across the rivers dividing the two countries.
They carry belongings and babies on top of their shoulders.
They must live in crowded, poorly kept shelters made from plastic covering and bamboo.
Refugees and aid groups say that when fighting stops, Thai officials send them back.
Myanmar's military, meanwhile, continues to take over villages, burn homes and set land mines.
"I have seen some of them being forced to get in a car, get off at the river, and cross over to the other side," said Phoe Thingyan of the aid group the Overseas Irrawaddy Association.
Win is a 23-year-old student who lives on the Myanmar side of the river.
He often crosses through chest-high water to get food from the Thai side.
Then he goes back to his shelter in Myanmar, where he lives with around 300 other refugees.
"I just want to go home," he said.
"I do not want anything else."
I'm Dan Novak.