The US is deporting 51 Cambodians who are expected to arrive in the country on Thursday, the single largest group of deportees in the history of the contentious 15-year repatriation program.

The group is expected to include deportees with chronic mental and physical health conditions, according to 1Love Cambodia, a support group for the returnees.

“We’ve been informed that contrary to US agreements, this group includes people with chronic mental and physical conditions that will require our community’s unwavering support,” the group said in a statement on its Facebook page. “We are hurt and enraged to say the least.”

Immigration chief Sok Phal could not be reached on Tuesday. However, Kim Vanny, a check-in official at Pochentong Airport in charge of arrivals, confirmed that officials are preparing to receive the returnees, but noted that the numbers can sometimes change.

“Sometimes the seniors change their mind and agree to not send,” Vanny said.

“So to be clear, on the day, they send their names to the airport. [Then] we will know [for] sure that they are coming.”

Brendan Raedy, a spokesman for US Immigration and Customs Enforcement, declined to comment. “Due to operational security, ICE does not comment on future removal flights until they have been completed,” he said.

As many as 200 Cambodians are expected to be deported from the US this year. By comparison, the Returnee Integration Support Center, now known as the Khmer Vulnerability Aid Organization, has received some 550 returnees over the past 15 years.

Most of the deportees entered the US as refugee children fleeing the Khmer Rouge with their families, and many have never been to Cambodia and don’t speak Khmer.

The deportation program created a diplomatic rift between the US and Cambodia last year after Cambodia stopped issuing travel documents to most of the deportees, prompting targeted visa sanctions by the US.

In February, US Assistant Secretary of State for Consular Affairs Carl Risch said visa sanctions on top Cambodian foreign affairs officials could be lifted “in the near future” if the Cambodian government followed through on promises to again accept returnees.

Jimmy Hiem, a member of 1Love Cambodia, said the group is collecting donations for “starter kits” for the returnees, such as portable stoves, pots, pans and toiletries.

Hiem, who was deported to Cambodia one and a half years ago, said he found the transition difficult with no relatives in the country and speaking little Khmer. He still does not have an ID, he said.

“There is a life after America, in my opinion,” Hiem said. “But they just have to not give up, and that’s what we’re trying to do, [to] help them navigate Cambodia.”