Nearly two dozen immigrants were allowed to cross the U.S.-Mexico border to seek asylum on Tuesday, the day the Trump administration planned to launch a drastic policy change designed to end asylum protections for most migrants who travel through another country to reach the United States.

The administration announced the plans a day earlier, reversing decades of U.S. policy in its most forceful attempt yet to slash the number of people seeking asylum in America. The new rule would cover countless would-be refugees, many of them fleeing violence and poverty in Central America. It is certain to face legal challenges.

At the crossing in Tijuana, Mexico, two asylum seekers who work closely with Mexican authorities called 12 people whose numbers were first on a waiting list to enter the through a San Diego border crossing. They were escorted behind a metal gate to a white van that left minutes later to turn them over to U.S. authorities.

At another crossing in Juarez, Mexico, 10 Cuban asylum seekers were called by Mexican officials and led across the Paso Del Norte Bridge to El Paso, where they were handed over to Customs and Border Protection officers, who began to process them. They were taken to a room where their possessions were searched, laid out on a table and bagged.

The few people who were allowed to cross were picked from many more immigrants who lined up at crossings. It’s unclear how officials will process their asylum claims under the new system. Lawyers who represent Cuban migrants say that they are not deportable because Cuba will not accept them.

“I’d rather be in prison the rest of my life than go back to Cuba,” said Dileber Urrista Sanchez, who had hoped his number would be called Tuesday, but he was further down the list.

Sanchez, 35, has waited with his wife in Juarez for the past two months, renting a room with money his mother sends him from Las Vegas.

He said his mother left Cuba years ago because she was part of an opposition party. In retaliation, he said, the government took away his job as a chauffeur, and he and his wife had been imprisoned for days at a time for being “untrustworthy.”

He criticized the Trump administration’s new policy, pointing out that the first country he was able to reach after leaving Cuba was Nicaragua.

“How are we going to apply for asylum in Nicaragua when it’s just as communist?” he said.

Derek Mbi of Cameroon was among nearly 50 migrants who gathered in Tijuana. He arrived there about a month ago, and more than 8,100 people were ahead of him on the waiting list.

Processing new arrivals has ground to a virtual halt to in recent days, down from an average of about 40 names a day.

Mbi, 29, joined a wave of Cameroonians who fled fierce government oppression against their country’s English-speaking minority by flying to Ecuador, which does not require a visa. From there, he traveled for months by bus and on foot through seven other countries to reach Tijuana.