MEXICO CITY (AP) — Mexican immigration authorities said Saturday they have been hit by a surge of almost 5,000 Haitian, African and Asian migrants entering by the southern border in just a few days.

Recent experience suggests the 4,749 migrants entering through Mexico's Tapachula immigration center on the Guatemalan border will soon try to reach the California border, with many expected to apply for asylum.

Mexico's National Immigration Institute said the migrants entered the country between Sept. 21 and 23. It did not break them down according to country of origin, but recent trends suggest the majority are likely from Haiti.

That would mark a huge increase over the number seen so far this year. The institute said a total of 7,800 Haitian migrants entered Mexico through Guatemala between Jan. 1 and Sept. 21, as well as 1,701 migrants from Africa and 3,753 from various Asian.

The institute said that none of these Haitian, African or Asian migrants have requested permission to stay in Mexico. "Up to this moment, the institute has not received any requests from these foreigners for refuge, asylum or regularization, because they have expressed that their desire is to reach the United States."

The migrants cannot be sent back to their home countries, so Mexico gives them 20-day temporary visas so they can cross the country and get to the U.S. It said the Africans came mainly from the Congo, Ghana, Guinea, Ethiopia, Eritrea, Somalia, Sudan and Nigeria.

However, this week the U.S. government said it was widening efforts to deport Haitians in response to the wave of thousands of immigrants from the Caribbean nation who have overwhelmed California border crossings with Mexico in recent months.

Mexico said that in Baja California alone, about 1,230 Haitian, African and Asian migrants are waiting for asylum in the United States, in many cases at border crossing gates or bridges.

The institute said Mexico was trying to provide the asylum seekers with food and water while they waited for a U.S. response.

Immigration and Customs Enforcement Director Sarah Saldana testified in Congress that other governments told her on a recent trip to Central America that 40,000 Haitians were on their way and called it an "emergency situation" on California's border.

A government move lifted special protections that shielded Haitians from deportation after their nation's 2010 earthquake.

The change may dramatically affect Haitians who have been showing up at U.S. border crossings in California, claiming they lived in Brazil for several years, left for economic reasons, and traveled through Central America and Mexico. Homeland Security officials say about 5,000 Haitians have been stopped at San Diego's San Ysidro port of entry since October, compared to only 339 for the 2015 fiscal year. Large numbers have also turned themselves in to U.S. inspectors in Calexico, California, 120 miles east of San Diego.

The influx is so heavy that inspectors at San Ysidro, the nation's busiest border crossing, are turning back Haitians with appointments to come at a later date, leaving hundreds waiting in Tijuana, Mexico. Many stay at one of the Mexican border city's five migrant shelters that volunteered in May to help.

The Rev. Pat Murphy, director of Casa del Migrante in Tijuana, said 90 percent of the people who have come to his shelter in the last six weeks are Haitians who moved to Brazil after the 2010 earthquake.