WASHINGTON – The number of border-crossers taken into U.S. custody topped 100,000 for the second consecutive month in April, U.S. border officials said Wednesday, deepening the crisis that has derailed President Donald Trump's immigration agenda and has defied his myriad attempts to fix it.

U.S. Customs and Border Protection (CBP) detained 109,144 migrants along the boundary with Mexico last month, a 6% increase from March, as monthly arrests reached their highest point since 2007. Unauthorized border crossings have more than doubled in the past year, and they are on pace to exceed 1 million on an annual basis, as Guatemalan and Honduran families continue streaming north in record numbers with the expectation they will be quickly processed and released from custody.

"Our apprehension numbers are off the charts," Carla Provost, chief of the Border Patrol, said in testimony to senators Wednesday. "We cannot address this crisis by shifting more resources. It's like holding a bucket under a faucet. It doesn't matter how many buckets we have if we can't turn off the flow."

"My greatest concern is that we will no longer be able to deliver consequences and we will lose control of the border," Provost said.

Trump has treated the monthly publication of border enforcement statistics as a performance index for his administration's immigration policies. The steady rise in migration has left him fuming and his administration scrambling for solutions. Trump's fury contributed to the removal of Kirstjen Nielsen as secretary of the Department of Homeland Security last month as part of a wider shake-up at the agency, with Trump vowing to go in a "tougher direction."

Toughness, for Trump, includes the deployment of razor wire, thousands of U.S. soldiers and plans to build hundreds of miles of barriers, as well as threats to close the border entirely.

White House officials have also turned to tightening the asylum claim process to make it more difficult for migrants to seek refuge in the country.