U.S. officials say San Diego’s border crossing has reached capacity even before a caravan of Central American migrants criticized by the Trump administration began turning themselves in to seek asylum.

A statement Sunday from U.S. Customs and Border Protection says the nation’s busiest border crossing can take in additional people as space and resources become available.

Packed into five old school buses, nearly 200 Central Americans who have spent a month traveling in a caravan through Mexico to the border with San Diego planned to seek asylum Sunday.

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

Officials had warned that San Diego’s San Ysidro crossing may not be able to take asylum seekers if it faces too many at once. The agency has said the port can hold about 300 people temporarily.

Asylum seekers are often released to family in the U.S. but some don’t have any and seek sponsors.

Supporters rallied on both sides of the border with a fence between them. Some climbed the 18-foot-high border wall separating San Diego and Tijuana to sit or wave signs under the watchful eyes of U.S. Border Patrol agents.