The Trump administration will deploy some 2,100 more troops to help “secure the southern land border of the United States”, the Defence Department said in a statement on Wednesday night.

Up to 1,000 of the troops will be members of the Texas National Guard.

About 750 of them will assist the Department of Homeland Security (DHS) “with operational, logistical, and administrative support” at “temporary adult migrant holding facilities” in Donna and Tornillo, Texas, according to the Pentagon statement.

“Migrants will be supervised by DHS law enforcement personnel,” it added.

Another 250 members of the guard force would be stationed at ports of entry along the US-Mexico border. About 1,000 active duty members of the armed forces would also be deployed in various roles, the Pentagon said.

'Dangerous' overcrowding of migrants in US border facilities Show all 6 1 /6 'Dangerous' overcrowding of migrants in US border facilities 'Dangerous' overcrowding of migrants in US border facilities Photos of detained migrants crowded into cells at the US border - with one holding up a sign reading simply "help" - have been released as part of a new report warning of "dangerous" overcrowding. The memo was sent to the Department of Homeland Security by its Inspector General, containing photos taken at border facilities in the Rio Grande Valley over a week in June DHS/OIG 'Dangerous' overcrowding of migrants in US border facilities Eighty-eight adult males held in a cell with a maximum capacity of 41, some signalling prolonged detention to OIG Staff on June 12 DHS/OIG 'Dangerous' overcrowding of migrants in US border facilities Overcrowding of families observed by OIG on June 11, at a border patrol facility in Weslaco, Texas DHS/OIG 'Dangerous' overcrowding of migrants in US border facilities Migrant families overcrowding a border patrol facility on June 11 in McAllen, Texas DHS/OIG 'Dangerous' overcrowding of migrants in US border facilities Fifty-one adult females held in a cell designated for male juveniles with a capacity for 40 at Border Patrol’s Fort Brown Station DHS/OIG 'Dangerous' overcrowding of migrants in US border facilities Migrant families overcrowding a border patrol facility on June 11 in McAllen, Texas DHS/OIG

As of 8 July, there were about 4,000 service members at the border, the Pentagon said on Wednesday night.

The announcement comes amid continuing rancorous debate regarding Donald Trump’s immigration policies and the treatment of undocumented migrants who have been apprehended while trying to cross into the US.

The Defence Department has been pulled into the fray. More and more troops are being sent to the border, and Mr Trump wants to use Pentagon funds to construct more than 100 miles of fencing along it.

The department said the new deployments had been approved by acting Secretary of Defence Richard Spencer.

The department has not had a permanent secretary since Jim Mattis resigned late last year.

Mr Trump has nominated Mark Esper for the post, and the Senate Armed Services Committee has been considering his nomination this week.

The US president has focused on cracking down on undocumented immigration – one of his signature issues – for weeks as his 2020 re-election campaign gets underway.

Trump says border wall would have prevented father and daughter from drowning in Rio Grande

He prodded Mexico to take steps to block migrants from crossing into the US after threatening the country with tariffs on goods last month.

Earlier this week, he moved to end asylum protections for most Central American migrants who cross the southern border.

About 6,000 active-duty US troops were deployed to the Mexican border last October, with Mr Trump saying they were needed to address a “national emergency” as caravans of asylum-seeking Central American migrants made their way towards the US.