Christopher Lapinig, at podium, an attorney at Asian Americans Advancing Justice-Los Angeles, is among lawyers for Vietnamese immigrants suing the federal government over their detention by U.S. immigration authorities, at a news conference in Santa Ana, Calif., Wednesday, Feb. 28, 2018. The lawyers say immigrants who arrived from Vietnam before the country resumed diplomatic relations with the United States in 1995 are not subject to a repatriation agreement between the countries, and thus their detention isn't legal. Also seen are Phi Nguyen, litigation director at Asian Americans Advancing Justice-Atlanta, center, and attorney Tuan Uong. (AP Photo/Amy Taxin)

SANTA ANA, Calif. - Vietnamese immigrants have filed a lawsuit alleging U.S. authorities are rounding them up and holding them in detention facilities for deportation — even though the Vietnamese government has not agreed to take them back.

Vietnam has only agreed to repatriate deportees who arrived in the United States after the two countries renewed diplomatic relations in 1995, the detainees' lawyers said Wednesday.

The attorneys for the detained immigrants believe the Trump administration has started arresting deportees who came to the country before that date to pressure Vietnam to broaden the repatriation agreement.

"They are just using this as an excuse to round up people indiscriminately in the hope they can then convince Vietnam to take them back," said Laboni Hoq, litigation director for Asian Americans Advancing Justice in Los Angeles.

Immigration and Customs Enforcement declined to comment on the lawsuit, which was filed last week in federal court in Southern California with three named plaintiffs and seeks class action status.

About 1.3 million Vietnamese immigrants live in the United States, according to the U.S. Census Bureau.

It wasn't immediately known how many arrived in the country before 1995, but many Vietnamese immigrants came as refugees after Saigon fell to communist forces in 1975.

As many as 10,000 Vietnamese immigrants have deportation orders, in many cases because they lost their green cards after criminal convictions, plaintiffs' lawyers said.

In the past, authorities would typically release the immigrants if they had arrived in the United States before 1995 because of a Supreme Court ruling that generally bars authorities from detaining immigrants after a reasonable period of time if there's no chance of deporting them.

But last year, authorities began arresting Vietnamese immigrants who had been in the United States for decades and were not subject to the repatriation agreement signed in 2008.

Plaintiff Long Nguyen, a 41-year-old resident of Charleston, South Carolina, came to the United States as a child in 1987, according to the lawsuit. He was issued a deportation order in 2012 after a drug charge and released from custody until October, when authorities pulled him over on his way to work and arrested him.

Plaintiffs' lawyers said at least 45 Vietnamese immigrants are involved in such cases and have been held for months.

Vietnamese immigrants were arrested in October in Georgia, Pennsylvania, Texas, Colorado and California, and many were interviewed by the Vietnamese consulate late last year, the lawsuit said.

In many communities, Vietnamese immigrants now fear they could be arrested even if they've lived in the U.S. for decades.

"I live day to day with uncertainty and fear," said Tung Nguyen, an ex-convict-turned community advocate in Orange County, California, who has a deportation order. "If you don't see me tomorrow, just remember me when I am gone."

News from © The Associated Press, 2018