The Trump administration and Republicans in Congress have been seeking new border security measures in exchange for permitting 800,000 young undocumented immigrants known as Dreamers to remain in the United States. On Tuesday, the president indicated he would even consider allowing millions more unauthorized immigrants to remain in the country, provided Congress took steps to keep new ones from entering.

The numbers of apprehensions are an indication of border activity, but they do not count those who slip through undetected. Though the recent increase makes clear that the flow of migrants has resumed, the numbers have not approached the crisis levels of 2014, when they reached nearly 70,000 in a single month, many of them children traveling alone. Homeland Security officials noted that the 2017 apprehensions still represented a 40 percent decrease from the year before.

“The final border apprehension numbers of 2017, specifically at the southern border, undeniably prove the effectiveness of President Trump’s commitment to securing our borders,” Tyler Houlton, a spokesman for the agency, said in a statement. He also called on Congress to close what he said were “loopholes” that incentivized illegal immigration and were being exploited by migrants. By that, he seemed to reference the asylum system, as well as special protections for children who cross the border without adult supervision.

Tens of thousands of people apply for asylum annually. The vast majority are denied, and cases can drag on for years, during which time many applicants are released from custody and establish ties to the United States, eventually deciding to stay illegally. Their numbers have contributed to an ever-growing immigration court backlog, with more than 650,000 cases now pending, up from 520,000 in late 2016, according to the Transactional Records Access Clearinghouse, a research group based at Syracuse University.

Among those stopped at the border in December were 8,000 families and 4,000 so-called unaccompanied minors. Family detention centers are so full that many families are being let go, with the parents fitted with ankle monitors, the kind of “catch and release” practice that the administration has been trying to avoid all along.

Responding to the growing number of people crossing the border, the White House late last year pulled together an interagency task force, which has been meeting to evaluate a suite of new deterrence policies, including separating parents from their children as their cases work through the courts, which immigration advocates have denounced as cruel.