US President Donald Trump has ordered border agents to begin a mass roundup as early as Sunday of some 2,000 migrant families that have received deportation orders, US media reported on Friday.

The news follows the president’s announcement on Twitter Monday that US Immigration and Customs Enforcement (ICE) officials would begin deporting “millions of illegal aliens,” although he gave little detail.

The tweet sped up operations that were already underway, according to unnamed sources cited by the Washington Post, NBC and CNN.

The family roundup is likely begin with pre-dawn raids in up to 10 cities including Houston, Chicago, New York and Miami.

Kevin McAleenan, the acting secretary of Homeland Security, is hesitant about parts of the operation, CNN reported.

He has been urging ICE to mainly focus on some 150 families that had attorneys but have dropped out of the legal process and vanished, the Post reported.

The US is facing a surge in migrants from several Central American countries plagued by gang violence and poverty. The numbers have hampered US authorities’ abilities to temporarily shelter and process arrivals.

Trump has called it “an invasion,” and has made the fight against illegal migration a central plank of his administration.

An estimated 10.5 million unauthorised immigrants are living in the United States, according to the Pew Research Center.

Migrant apprehensions have soared to 144,000, including 57,000 minors, in May — the highest number in 13 years.

Congress has authorised ICE to detain 40,000 migrants, and many others are sent to other overcrowded facilities across the nation.

In 2017 the Trump administration imposed a “zero tolerance” regime on the US border with Mexico, which resulted in hundreds of families being split up.

Separately, Texas Republican Governor Greg Abbott announced on Friday that he will send another 1,000 National Guard troops to the US-Mexico border while accusing Congress of failing to take action on the growing humanitarian crisis.

The governor said at an afternoon press conference among Republican leaders and Major General Tracy Norris that additional guards will assist at new detention facilities in the Rio Grande Valley and El Paso and at ports of entry.

It brings the total number of Guard members on the Texas border to more than 2,000, Republican Lieutenant Governor Dan Patrick said. There are also 1,400 active-duty soldiers who remain on the border, according to an Army spokesman.

“My message to them is Congress is a group of reprobates for not addressing a crisis on our border and we’re not going to stand idly by and endanger the lives and safety of the state of Texas because Congress is refusing to do its job,” Abbott said.

Those troops will help facilitate commercial traffic coming across the border and work in collaboration with Border Patrol, Abbott added.

He said the federal government will fully fund the additional Guard Deployment.

Texas’ top Republican leaders renewed their attacks on Congress after reports that a Texas border facility is neglecting migrant kids. Government facilities are overcrowded, and five immigrant children have died since late last year after being detained by Customs and Border Protection.

A teenage mother with a premature baby was found last week in a Texas Border Patrol processing center after being held for nine days by the government.

Abbott’s announcement came after House Democrats unveiled a $4.5 billion border measure on Friday.

Democrats in Texas criticised the new deployment as reckless and unnecessary while harming the United States’ relationship with allies in Mexico and Central America.

“Deploying more National Guard to the border is a fool’s errand and a waste of millions of taxpayer dollars. This latest action will not help to alleviate the humanitarian crisis at our southern border,” Senate Democratic Leader Jose Rodriguez of El Paso said in a statement.

Texas has used National Guard members on the border since 2014, when then-Gov. Rick Perry also deployed 1,000 guardsman. Texas has also spent billions of dollars in border security over the last decade, including assigning more state troopers to the southern region.

Agencies