WASHINGTON, D.C. (NEXSTAR) — As more and more busloads of migrants arrive to the nation’s capital, Washington D.C. Mayor Bowser says the city is now at a tipping point.

“We need the federal government to be involved,” Bowser said.

She’s calling for 150 National Guard troops a day to help and to set up a processing center in the district.

Bowser said she expects the humanitarian crisis to escalate.

In April, as a response to an influx at the southern border, Texas Gov. Greg Abbott began sending buses full of migrants from Texas to sanctuary cities, like Washington D.C. So far, the city estimates that nearly 200 buses have arrived, delivering more than 4,000 migrants.

White House Press Secretary Karine Jean-Pierre accused Republican governors of using migrants as a political tool.

“There’s a process in place for managing migrants at the border — this is not it,” Jean-Pierre said.

But Republicans fired back, saying D.C. is experiencing just a fraction of what border communities experience every day.

The Department of Defense says the mayor’s request is now under consideration.