Immigration and Customs Enforcement officers arrested more than 150 people nationwide in an operation that targeted illegal immigrants who had asked the courts for permission to self-deport rather than be forcibly removed, then failed to leave.

“During the past two weeks, ICE’s Enforcement and Removal Operations located 154 aliens who received an order of voluntary departure but refused to leave the United States,” Senior Official Performing the Duties of ICE Director Tony Pham said during a press conference in McAllen, Texas, Thursday. “You must keep your promise to the United States, and depart within the agreed-upon time frame. Anyone with a voluntary departure order who fails to depart will face imminent removal from the country. This is just the beginning of the operation.”