President Joe Biden cast blame on the Trump administration for the mass migration that has engulfed the U.S. southern border since January and hurt his chances at passing immigration reform in his first 100 days.

“When I was vice president, I focused on providing the help needed to address these root causes of migration. It helped keep people in their own countries instead of being forced to leave. Our plan worked, but the last administration shut it down,” Biden said in prepared remarks for a speech before select members of Congress on Capitol Hill Wednesday night.