WASHINGTON (AP) — The number of migrant children and families seeking to cross the U.S. southwest border has surged to levels not seen since before the pandemic, a challenge for President Joe Biden as he works to undo the restrictive immigration policies of his predecessor.

Statistics released Wednesday by U.S. Customs and Border Protection showed the number of children and families increased by more than 100 percent between January and February. Kids crossing by themselves rose 60% to more than 9,400, forcing the government to look for new places to hold them temporarily.

The Biden administration is temporarily holding children and families, mostly from Central America, in government and private facilities for several days while it evaluates claims for asylum or determines if they have any other legal right to stay in the U.S.

It is a challenge for an administration that has been working to restore an asylum system largely dismantled under Trump and likely to face increasing pressure. Driving the increase is widespread hunger in Central America due to recent hurricanes, the economic upheaval of the pandemic and more fundamental social problems dating back years.

“If you put all those issues together you are going to see folks that are looking for a better way of life,” acting CBP Commissioner Troy Miller said as he presented the latest figures.

Republicans have argued that migrants are drawn by incentives such as the immigration bill backed by Biden and many Democrats that would offer a path to citizenship for millions of people illegally in the country. “We’re seeing a surge of unaccompanied children coming across the border. Why? Joe Biden promised amnesty,” Sen. Ted Cruz, R-Texas, said in a tweet.

Overall encounters have been increasing steadily since April 2020, soon after Mexico and the U.S. agreed to close the official border crossings to all but essential traffic because of the pandemic.

There were nearly 29,000 family units or unaccompanied minors in February. The last time it was higher was in October 2019.

Biden officials have faced mounting questions about the temporary detention of migrant families, an issue that the two previous presidents had to deal with because of the instability in the region. The new administration is seeking to craft a softer approach.

Roberta Jacobson, Biden’s senior official for southwest border affairs and a former U.S. ambassador to Mexico, said the administration is asking Congress for $4 billion for targeted aid to nonprofit and community organizations in Honduras, El Salvador and Guatemala to try to ease some of the conditions that cause people to flee their homelands.

“Only by addressing those root causes can we break the cycle of desperation and provide hope for families who clearly would prefer to stay in their countries and provide a better future for their children,” she told reporters at the White House.

Jacobson said the U.S. is also restoring a program, ended under Trump, that reunited children in the three Central American countries with parents who are legal residents in the United States.

The Department of Homeland Security has also begun processing the asylum claims of thousands of people who were forced by the Trump administration to stay in Mexico, often in dangerous conditions, for a decision on their case.

U.S. officials say that early Biden administration moves on immigration have likely been incorrectly portrayed by smugglers to migrants that they will be able to cross the southwest border more easily than under Trump. Most people are still turned back.

Nearly three-quarters of the more than 100,000 total people encountered at the southwest border in February were single adults, records show, and the vast majority were turned back to Mexico under the public health order.