TIJUANA, Mexico (AP) — The Latest on a caravan of Central Americans seeking asylum in the United States (all times local):

8 p.m.

Central Americans who traveled in a caravan through Mexico to the border with San Diego have begun turning themselves in to U.S. authorities to seek asylum in a challenge to the Trump administration.

The migrants began applying for protection at the nation's busiest border crossing Monday after immigration officials said the facility didn't have space to accommodate the group.

U.S. Customs and Border Protection said didn't say how many were allowed in late Monday but project organizer Alex Mensing of Pueblo Sin Fronteras said there were eight.

It marked the end of a monthlong journey by foot, freight train and bus for the migrants, many of whom are fleeing violence in their home countries.

The caravan got attention after President Donald Trump and members of his Cabinet called it a threat to the United States.

4:35 p.m.

President Donald Trump says a caravan of Central American migrants seeking asylum in the U.S. shows the weakness of the nation's immigration laws.

Reacting to news that the group reached the U.S. border over the weekend, Trump tweeted Monday that the group is "openly defying our border."

He called out Democrats for supporting "sanctuary city" policies that limit local police cooperation with federal immigration authorities.

Trump and other members of his administration have been watching and criticizing the caravan of hundreds of Central Americans since they started journeying through Mexico a month ago.

The migrants tried to start applying for protection at the San Diego border crossing Sunday. But U.S. officials have said for two days that the facility is full and can't accommodate them.

10 a.m.

About 200 asylum seekers in a caravan of Central Americans are not being allowed to turn themselves in to U.S. border inspectors for a second straight day.

U.S. Customs and Border Protection says a San Diego border crossing facility has reached capacity.

Mexican authorities allowed about 50 people to cross a long bridge leading to the U.S. inspection facility on Sunday but U.S. authorities told them to wait.

Customs and Border Protection says it will resume processing when it has more space and resources.

Irineo Mujica of Pueblos Sin Fronteras, the group organizing the caravan, says the U.S. refusal is a "farce" aimed at avoiding having to deal with the Central American asylum seekers.

About 50 asylum seekers camped overnight on a sidewalk outside the Mexican entrance to the border crossing.