Amid a recent surge in arrests of immigrants allegedly living in the country illegally, some raids by U.S. Immigration and Customs Enforcement have drawn quiet concern from Republicans in Congress who largely back President Donald Trump’s mass-deportation project.

They are also encouraging migrants in the U.S. to return to their home countries on their own. Trump has offered $1,000 and a free commercial flight to people willing to “self deport.” But even with that incentive, immigrants aren’t leaving the country at the pace Trump promised.

Former officials said the Trump administration’s push for the agency to detain record numbers of undocumented immigrants increases the chances of mistakes.

Trump officials are looking to tent companies, private prison operators and disaster-relief providers for a “massive expansion” of immigration detention facilities, according to a new report

Many of the people arrested at appointments had been released under a program for those deemed not to be threats to public safety.

Arrests by Immigration and Customs Enforcement during President Trump's second term topped 100,000 this week, as federal agents intensified efforts to detain unauthorized immigrants in courthouses, worksites and communities across the U.S., internal government data obtained by CBS News shows.

Immigration and Customs Enforcement agents — often dressed in plainclothes — are now arresting immigrants at courthouses nationwide, sometimes moments after their hearings end. Why it matters: The courthouse crackdown is part of a sweeping Trump administration effort to fast-track removals and increase the number of deportations this year — a strategy that's dramatically expanding who gets targeted and how.

In emails sent to rank-and-file agents last weekend, leaders suggested that agents get creative to detain more suspects.

The latest arrests suggest tensions are increasing ahead of the weekend, when more demonstrations are planned.

Protests against President Donald Trump's immigration crackdown and ICE raids have emerged across the U.S., including in Iowa. Here's what to know.

As Donald Trump revamps his promised nationwide crackdown on immigration, federal authorities are taking more aggressive measures to detain immigrants.