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WASHINGTON — As the government shutdown drags on, lawyers from the White House, the Department of Homeland Security and the Pentagon are meeting to discuss whether President Donald Trump can declare a national emergency to deploy troops and Defense Department resources to build his border wall, according to two sources with knowledge of the discussions.

One of the sources, a senior administration official, said the White House has kept this option on the table for some time, but is now considering it more seriously.

"Depending on the severity of crisis, it’s always been an option. Now that things are getting worse, we are looking at how that could be operationalized and used to confront the crisis," the official said, speaking on the condition of anonymity.

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The official said the talks are ongoing and will continue over the weekend as details are worked out.

ABC News first reported that the White House was considering declaring a national emergency to build the wall.

Trump said at a press briefing Friday he was considering declaring a national emergency in order to bypass Congress.

"We can call a national emergency because of the security of our country," Trump said at the press briefing in the Rose Garden.

However, the numbers of border crossers are not at all-time highs. Fiscal year 2018, which ended Sept. 30, saw a lower numbers of illegal border crossings than fiscal year 2014 or fiscal year 2016.

Asked if the Department of Defense was open to the idea of using its resources to build the wall, the official simply said the president would use his power as the commander in chief.

The official did not rule out that the Federal Emergency Management Administration, a part of DHS, may also be used as part of a national emergency response.