U.S. authorities made more than 69,000 arrests and detentions last month along the border with Mexico, a 21 percent increase from September and the highest total for any October since 2005, according to U.S. Customs and Border Protection figures released Thursday.

The increase was partly fueled by a soaring number of repeat arrests along the border resulting from the Trump administration’s practice of quickly “expelling” people to Mexico after they enter the country illegally.

CBP officials insist the expulsions are a crucial public health measure to prevent the additional transmission of the coronavirus inside the United States, but many of those sent back across the border are trying to enter again and again, without risk of detention and criminal prosecution. The most recent figures indicate that at least one-third of those taken into custody each month are repeat offenders.

Mark Morgan, the acting commissioner of CBP, once more used his monthly enforcement briefing to depict border crossers as selfish and unconcerned for the welfare of U.S. agents and the American public.

“They’re telling us their wants and needs are more important than our lives,” Morgan told reporters. “Their economic conditions more important than the lives of American citizens.”

It was an argument similar to the one made by those who have urged a national mask mandate, which President Trump has opposed. But Morgan said the migrants present a unique threat because of their lack of masks and the cramped conditions in which they travel to the border.

The acting commissioner blamed the economic impacts of the pandemic for the latest increase in border crossings, as well as President-elect Joe Biden’s stated plans to reverse many of Trump’s immigration policies. “Anticipated shifts in policy are creating new pull factors,” Morgan said, referring to the mix of incentives that typically motivate people to make the journey north.

Though Trump took office promising tight immigration controls and a border wall, illegal crossings have surged repeatedly during his term. The Trump administration has completed more than 400 miles of gigantic steel barriers so far, part of a $15 billion effort that administration officials insist is critical to stopping illegal migration.

Trump is now on track to leave office in January with border arrests nearing 100,000 per month, a level reached several times in 2019 and far higher than any month during President Barack Obama’s administration.

The latest CBP figures show the flow of illegal narcotics into the United States also increased dramatically in October.

While it can be difficult to know whether increases in seizures are a result of more narcotics entering the country or merely an improvement in interdictions, the quantities reported last month point to intensifying trafficking activity, according to CBP.

Seizures of cocaine at the border in October were 63 percent higher than last year, CBP deputy commissioner Robert Perez said. Methamphetamine seizures rose 41 percent, heroin was up 181 percent and CBP confiscated 300 percent more fentanyl than in October 2019, he said.

With cross-border vehicle traffic limited to essential travel, most of the narcotics were detected inside commercial cargo loads, Perez said.

“Despite the pandemic, our reality is that drug smugglers continue to push this poison across our borders using every conceivable smuggling method,” he said. “Despite restrictions on nonessential travel, that didn’t deter criminals from changing tactics.”