What to Know US border authorities handled 67 percent more claims for asylum as of Sept. 2018 than they did in the previous year.

Judges granted asylum in 21 percent of their cases in the 2018 fiscal year.

On Wednesday, a federal judge struck down Trump asylum rules for domestic and gang violence victims.

Undocumented immigrants seeking asylum in the United States will be told to wait in Mexico while their claims are processed, according to a new U.S. policy to which Mexico has agreed.

Department of Homeland Security Secretary Kirstjen Nielsen explained the new process in remarks to Congress Thursday, saying undocumented immigrants without the proper documentation will have to await approval to come into the U.S. until they are granted asylum by a U.S. judge.

"They will not be able to disappear into the U.S.," Nielsen said of those asking the U.S. for protection due to race, religion, nationality, political opinion or membership of a social group.

"They will have to wait for approval to come into the United States. If they are granted asylum by a U.S. judge, they will be welcomed into America. If they are not, they will be removed to their home countries."

Nielsen said that Mexican officials have agreed to this policy change and the decision was a historic one for the country, which has traditionally refused to accept the return of any migrants who aren't Mexican.

Mexico's Foreign Relations Department said Thursday the move is a temporary, humanitarian measure. The country will offer visas for those seeking asylum in the U.S. to stay on Mexican soil and apply for work and other government protections.

Under current policy, people eligible for asylum may be permitted to remain in the U.S. and file for asylum within one year of their arrival.

Last week, U.S. Customs and Border Protection officials said the agency has experienced a 121 percent increase in the number of asylum seekers at ports of entry across the U.S.

Almost 93,000 claims were processed by the CBP in the fiscal year 2018, a spokesperson told NBC 7 San Diego.

Applicants currently may be released into the U.S., often with ankle monitors, while their cases wind through an overwhelmed system of immigration courts.

Jackie Wasiluk with CBP Public Affairs said the port of entry facilities were not designed to hold hundreds of people at a time while they seek asylum. She added that the agency is also charged with monitoring trade and travel and keeping illicit goods and drugs from crossing into the U.S.

Judges granted asylum in 21 percent of their cases in the 2018 fiscal year, according to the Associated Press.

The Associated Press contributed to this report.