U.S. Immigration and Customs Enforcement has tested more than 300 detainees for the COVID-19 virus and 124 of them were positive, or more than one-third, CQ Roll Call learned Friday, raising concern among immigration advocates that the actual number of ill detainees held by the agency is far greater.

ICE, which currently has 32,000 people in custody, confirmed that tests have been given to more than 300 detainees. However, at least two other sources briefed on the agency’s COVID-19 operations quoted a range from around 200 to nearly 400 when asked by CQ Roll Call about test numbers.

Late Friday night, the House Oversight and Reform Committee released its notes from a briefing with Matthew Albence, the acting director of ICE, in which Albence said 400 people had so far been tested, but noted the agency did not always test people before deporting them back to their home countries.

Rep. Jamie Raskin, D-Md., who chairs the panel's civil rights and civil liberties subcommittee, on Friday said the briefing left him troubled: "It confirmed that its testing of detainees and staff is as sporadic and flawed as the federal government’s overall approach to public testing."

ICE’s public tally on its website Friday said the total number of COVID-19 positive detainees was 105, and that 25 detention staff and 81 employees not assigned to detention facilities have also tested positive. But on Friday evening, ICE informed congressional staff that 19 additional detainees had tested positive. Once a detainee tests positive, everyone in contact with the person is isolated together in their living spaces and on lockdown for most of the day, ICE has previously said.