(The Center Square) – The city of Denver is under an official state of emergency following an influx of migrants from the U.S. border with Mexico.

Mayor Michael Hancock issued the emergency declaration  Thursday, saying 247 migrants have arrived since Monday.

“This influx of migrants, the unanticipated nature of their arrival, and our current space and staffing challenges have put an immense strain on city resources to the level where they’re on the verge of reaching a breaking point,” Hancock said.

Over 900 migrants have arrived in the city in recent months, and roughly 400 are being sheltered in facilities, according to the mayor’s office.

The declaration will allow the city to “access additional emergency resources.” As of Thursday, the city has spent $800,000 to operate an emergency center, Hancock said.

The mayor said staffing and shelter remain the areas of most significant concern and pleaded with nonprofit groups to help shelter migrants.

Friday, the city posted job listings for “short-term shelter assistants” to work with migrants. The city pays $25 an hour for the positions.

The federal government estimates that nearly 78,000 foreign nationals illegally entered the U.S.’s southern border near El Paso last month.