70,000 migrants were caught crossing the Southwest border of the U.S. last month — a 64% increase compared to last November that came in spite of the pandemic and strict immigration enforcement policies, border officials told reporters Monday.

Driving the news: Acting Customsand Border Protection Commissioner Mark Morgan — a Trump appointee with hardline immigration views — sought to blame the increase in the waning days of the administration on the courts and President-elect Joe Biden's stated immigration platform.

By the numbers: In addition to the overall surge, there have also been more migrants and minors from El Salvador, Guatemala and Honduras, countries that have suffered from recent hurricanes.

• The number of unaccompanied children encountered at the U.S.-Mexico border rose from 712 in April to roughly 4,700 in October and 4,500 in November, Morgan said.

Between the lines: Unlike past surges, smugglers have been trying to sneak minors further into the U.S. through remote areas, notes Axios' Russell Contreras.

• Because the 2019 crisis was fueled by large numbers of migrant families and children from the Northern Triangle — El Salvador, Guatemala and Honduras — border officials pay close attention to those trends.

What they're saying: Morgan blamed rising numbers on court rulings, including one in November that prevented border officials from quickly expelling minors who cross the border alone. However, the number of unaccompanied minors who crossed the border decreased slightly between October and November.

• Morgan suggested Biden had also contributed to the trends at the border, saying "cartels and human smugglers are fueling perceptions that our borders will once again be wide open, and that we will be reinstating the loopholes that have been closed."
• "If your policy consists of stopping deportation for almost four months, discontinuing or not supporting title 42, revoking the migrant protection protocols," Morgan said, listing off other elements of Biden's immigration platform, "the message you're sending is clear and simple: We have open borders."
• He added that he would love to speak to the Biden transition team about his concerns, but had not yet.

Reality check: Immigration flows are complex. While American politics can play a role, the pandemic, economic instability and hurricanes have also pushed Central Americans to flee their home countries.

What to watch: If border crossings continue to rise, the Biden administration may need to be even more cautious and methodical in deciding how and whether to change Trump's border policies, Leon Fresco, an immigration attorney who worked at the Justice Department under President Obama, told Axios.

• Morgan also told reporters that the administration is on track to complete its goal of building 450 miles of border wall by the end of the year.