Hundreds of the people who were arrested had been enrolled in ICE’s Alternative to Detention (ATD) program, three sources familiar with the arrests said. Under the program, ICE releases undocumented immigrants who are deemed not to be threats to public safety and then keeps track of them through ankle monitors, smartphone apps or other geolocating programs, along with periodic check-ins at ICE facilities.

At least some of the arrests appear to be the result of a new ICE tactic: Immigration attorneys across the country told NBC News that some of their clients on ATD were asked in a mass text message ICE sent out to show up ahead of schedule for check-ins at ICE offices, only to be arrested when they arrived. (snip)

Veronica Navarrete was waiting outside the immigration office for a friend, an asylum-seeker from Ecuador, who had been told to report to the office Wednesday. She told NBC News she had seen immigrants pacing outside the building all day, some of them seeming to her to be contemplating whether to show up for their appointments at all.

“If you enter, there’s a possibility that they’ll take you into custody,” she said. “And if you don’t enter, you’ve missed your appointment, and that’s automatic deportation. We have no way out.”