Seven U.S. senators, including Susan Collins and Angus King, have visited the Texas-Mexico border on a fact-finding mission focusing on the immigration crisis.

The group met Friday with Customs and Border Patrol Commissioner Gil Kerlikowske during a visit to a border patrol station, port of entry and centralized processing center. They also visited a military base that’s housing thousands of unaccompanied children from Central America who have crossed the U.S. border.

Collins organized the trip. Other participants were Sens. John Cornyn of Texas, John Barrasso of Wyoming, John Boozman of Arkansas, Deb Fisher of Nebraska and Heidi Heitkamp of North Dakota.