Some people caught in Trump administration immigration operations have already been released back into the United States on a monitoring program.

Despite the president’s campaign promises to carry out the “largest deportation operation in American history,” some migrants rounded up by Immigration and Customs Enforcement (ICE) are currently being released back into the country due to space constraints.

The weekend operation follows President Trump’s vows to deport millions of undocumented immigrants, which he calls the “largest deportation program in American history.”