The official, who spoke on condition of anonymity, said the Department of Homeland Security had requested certain "capabilities," and that the Pentagon would determine what troops or equipment would be needed to accomplish their mission.

Nearly 5,600 troops currently are deployed along the US-Mexico border, in support of the border patrol, which falls under DHS.

US President Donald Trump announced the deployment shortly before the November 6 midterm elections, as several thousand Central American migrants made their way to the border to seek asylum from violence and poverty in their own countries.

The unusual deployment was supposed to end in mid-December, but DHS asked that it be extended until January 31 in light of what it said was a continued threat to national security.

According to several US media, soldiers could be deployed along the border in California and Arizona, but that could be accomplished by simply repositioning troops already in the area rather than sending in reinforcements.

A military source speaking on condition of anonymity said the latest DHS request did not anticipate deployments beyond January 31.

On Friday, Trump was meeting with Democratic and Republican leaders to try to end a two-week-old government shutdown, precipitated by an impasse over his demands for funds to build a border wall.

Newly empowered Democrats, who regained control of the House of Representatives on Thursday, have shown little inclination to bend to his demands for $5.6 billion in wall funding.