The helicopter had taken off from an Army aviation facility in St. Cloud.

A Minnesota Army National Guard helicopter with three people aboard was missing after having taken off from an Army aviation facility in St. Cloud, Minnesota, on Thursday, according to a National Guard spokesman.

The UH-60 Black Hawk lost communication with the tower about 2:05 p.m. on Thursday while it was conducting a maintenance test flight, according to the Minnesota National Guard.

Information about the helicopter’s flight destination was not immediately available, according to Army Col. Joe Sharkey, director of communications for the Minnesota National Guard.

A search effort for the Black Hawk was underway.

“The Minnesota Army National Guard is currently trying to work with local authorities in St. Cloud based on its flight pattern,” Sharkey told ABC News.

The St. Paul Fire Department said in a tweet on Thursday that it had deployed a rescue squadron following reports of the missing aircraft.

“Our first priority is the safety and well-being of our Guardsmen and our thoughts are with our soldiers and their families at this time,” the Minnesota National Guard said.

In September, one soldier was killed and three others were injured during an Army helicopter accident at the Joint Readiness Training Center and Fort Polk training area in Louisiana.

A spokesperson for Fort Polk told ABC News at the time that the helicopter was a UH-60 Black Hawk medevac unit comprised of four soldiers that crashed while en route to pick up another soldier needing treatment for heat-related symptoms.

It was unclear what caused that crash, but the spokesperson said that the weather was clear and the helicopter did not strike power lines.

Then in November, two Apache pilots were killed during a helicopter crash in eastern Afghanistan. Initial indications were that the helicopter was not brought down by enemy fire.

This is a breaking story. Please check back for updates.