TIJUANA/MEXICO CITY (REUTERS) - The United States sent the first Central American asylum seeker back to Mexico through a crossing at the border city of Tijuana on Tuesday (Jan 29), Mexican authorities said, as part of the Trump administration's hardened immigration policy.

The return of a Honduran man was carried out under a US policy dubbed the Migrant Protection Protocols (MPP) by which the United States will return non-Mexican migrants who cross the US southern border back to Mexico while their asylum requests are processed in US immigration courts.

The United States is not expected to send any other Central American migrants to Mexico on Tuesday, said a Mexican immigration official, who asked not to be identified.

A US Department of Homeland Security spokesman confirmed earlier in the day that the United States would begin sending migrants back to Mexico on Tuesday.

Mexican officials had initially expected the transfers to begin on Friday.

The interior ministry identified the returned Honduran migrant as Carlos Gomez, 55, who entered Mexico last year and has been given a humanitarian visa to remain in Mexico through late November.

Asylum seekers have traditionally been granted the right to stay in the United States while their cases were decided by an immigration judge, but a backlog of more than 800,000 cases means the process can take years.

US authorities are expected to send as many as 20 people per day through the Mexican border city of Tijuana and gradually start sending people back through the other legal ports of entry, Mexico's foreign ministry has said.

The US policy is aimed at curbing the increasing number of families arriving mostly from Central America to request asylum who say they fear returning home because of threats of violence there. The administration of US President Donald Trump says many of the claims are not valid.

Mexico has said it will accept the return of certain people who have a date to appear in a US court, but will reject those who have health problems, are unaccompanied minors or would be in danger in Mexican territory.

Immigration advocates fear Mexico is not safe for migrants, who are regularly kidnapped by criminal gangs and smugglers. They have also raised concerns that applicants sent back to Mexico will not have access to proper legal counsel in US courts.