New York has moved to curb a Texas policy of busing thousands of migrants to the city, part of a growing battle over immigration that is already a core campaign issue ahead of 2024 presidential polls.

Mayor Eric Adams ordered that buses carrying migrants from the southern border with Mexico must give 32-hours notice before arriving in the city, and limited the times when such charter services can drop off passengers.

Texas Governor Greg Abbot has chartered coaches to move newly-arrived migrants from the border to New York in protest at what he claims are the national government's failings in the face of migrants flows. 

New York's move issued late Wednesday came after Adams met with his fellow Democratic mayors of Chicago and Denver, also popular destinations for newly-arrived migrants. 

They called for greater action from national authorities which Adams has repeatedly attacked for inaction.

"Just last week, 14 chartered buses with migrants arrived overnight from Texas, the highest recorded number in a single night," said Adams.

"Cities cannot continue to do the federal government's job for them. We need federal and state help to resettle and support the remaining 68,000 migrants currently in New York City's care."

New York, a megacity of 8.5 million inhabitants, has welcomed waves of migrants throughout its history and more than 161,500 asylum seekers have arrived since spring 2022, city hall says.

Central political issue

Over 68,000 of them are still being cared for by the city which has opened 214 sites to shelter them, mostly repurposed hotels.

The influx of migrants has become a central issue as campaigning ramps up ahead of next year's presidential polls and the United States has seen record numbers of arrivals on its southern border.

The number of people seeking to enter the United States without authorization had shot up this month to around 10,000 a day, nearly double the number from before the coronavirus pandemic.

Few migrants are Mexicans, with the bulk in recent years fleeing Central American countries which have been ravaged by extreme poverty, rampant violence and failing crops worsened by climate change.

"We only want to work. I'm not asking and have never asked for anything for free," Maynor Estuardo Villegas, a migrant from Guatemala, told AFP in the southern Mexican town of Escuintla as he made his way toward the United States in a migrant caravan.

Secretary of State Antony Blinken paid an unusual Christmas week visit to Mexico City to tackle the issue as the rival Republican Party presses US President Joe Biden for a migration crackdown in return for agreeing in Congress to extend support for Ukraine.

Immigration is a top issue for Republicans heading into a general election year, and Democrats in swing states are vulnerable.

In the year to the end of September 2023, border patrol officers logged a record high 2.4 million encounters with migrants at both official ports of entry and elsewhere along the southern border.

Busloads of migrants have been arriving in New York city, sometimes at a Manhattan bus station, with many then going on to seek shelter and assistance from city authorities which are legally obliged to provide it.

"We really are saying to bus operators and companies — do not participate in Governor Abbott's actions," Adams said Wednesday.