Activists say ICE placed 20 detainees in solitary confinement as punishment for participating in protest to end deportations

US immigration and customs enforcement (ICE) has retaliated against about 20 immigrant hunger strikers and supporters at a Washington detention facility by sticking them in solitary confinement, activists said Thursday, and two legal groups sued to halt the practice.

The agency denied exacting any revenge, saying instead that those separated from the general population had been generating complaints by intimidating others to join the strike. "While ICE fully respects the rights of all people to express their opinion without interference, when these expressions infringe on the civil rights of others, ICE has an obligation to act," the agency said in an email.

At least 750 detainees participated in a hunger strike about a month ago to protest US immigration law as well as the conditions at the Northwest Detention Center in Tacoma, Washington, which houses nearly 1,300 people being investigated for possible deportation. Some began a renewed hunger strike 24 March.

Three days later, guards asked several detainees if they wanted to meet with an assistant warden. After they raised their hands, they were handcuffed and placed in solitary confinement, activists said.

The American Civil Liberties Union (ACLU) of Washington and Columbia Legal Services sued ICE and said they're asking a federal judge in Tacoma for a temporary restraining order to halt the practice. A hearing was set for Friday morning.

"Retaliating against and punishing immigrant detainees engaged in peaceful protests is an unlawful attempt to chill free speech rights," state ACLU legal director Sarah Dunne said in a written statement. "Like all civil detainees, they have free speech rights protected by the Bill of Rights."

In affidavits filed with the court, three detainees named as plaintiffs said they had done nothing to intimidate others.

"I cannot challenge the allegations against me because I have not been given any information about what I allegedly did to intimidate others," said one, Ericson Gonzales.

The three have spent 23 hours per day in isolated cells, with one hour alone in a small yard, they said.

The strikers have sought an end to deportations as well better conditions at the center, including better food and better pay for the jobs they perform in confinement.

In a news release, activist Jolinda Stephens said the last of the original hunger-striking group, Jesus Gaspar Navarro, ended his fast after 25 days on Tuesday. He spoke on-air with a Spanish-language radio station, and then was removed from medical isolation to solitary confinement, she said.