A senior US immigration official has said that authorities plan to release thousands of migrants from detention amid a severe budget crunch.

The official from Immigration and Customs Enforcement (ICE) told CBS, the BBC's US partner that between 4,000 and 6,000 migrants could be released.

A bipartisan border bill that would have funded immigration detentions collapsed last week.

More than 6.3 million migrants have entered the US illegally since 2021.

ICE is currently holding about 38,000 migrants in long-term detention facilities.

The bipartisan border bill that faltered due to Republican opposition last week would have earmarked $7.6bn (£6bn) for ICE, including an additional $3.2bn for detention capacity that would have boosted the agency's ability to house detainees by several thousand beds.

According to the Washington Post - which first reported the story - the bill's collapse prompted ICE officials to circulate an internal proposal to slash costs by cutting detentions from 38,000 to 22,000.

While the proposal would see some of the migrants deported back to their home countries, many would be released into the US, the report added.

In response to a query from the BBC, a spokesperson for the Department of Homeland Security (DHS) - which includes ICE - said that Congress has "chronically underfunded" efforts to secure the border.

The rejection of the border bill, the spokesperson added, will "put at risk DHS's current removal operations" and "put further strain on our already overtaxed workforce".

The spokesperson said that without "adequate funding" for Customs and Border Patrol, ICE and US Citizenship and Immigration Services, "the department will have to reprogram or pull resources from other efforts".

A budget shortfall would also mean that ICE's capacity to deport migrants would suffer, one of a number of potential changes to DHS operations cited by the spokesperson.

Any such move would almost certainly face intense criticism from Republicans, who have long called for stricter enforcement and fewer migrants being "paroled" into the US to await immigration court proceedings.

The border has become an extremely divisive issue in the US.

A January poll conducted by CBS - the BBC's US partner - suggests that nearly half of Americans view the situation at the border as a crisis, with 63% wanting "tougher" policies.

More migrants have been held while crossing the border illegally since the start of President Joe Biden's term than under either Donald Trump, Barack Obama or George W Bush.

Of the more than 6.3 million total, about 2.4 million have been allowed into the US, mostly to await decisions from immigration courts.

On a monthly basis, migrant detentions rose to an all-time high of over 302,000 in December 2023, but fell by 50% to about 124,000 in January.

CBP officials have attributed the drastic decline to "seasonal trends, as well as enhanced enforcement efforts".

Experts have also credited increased enforcement by the Mexican government for the drop in migrants "encounters" at the border in the wake of a December meeting between Secretary of State Antony Blinken and Mexican President Andrés Manuel López Obrador. (BBC)

Update news