Two D.C. police officers were hospitalized in serious condition after being hit by a vehicle Monday while helping the driver of another car in Southeast Washington, authorities said.

The officers, who were attending to the motorist on a ramp near Interstates 295 and 695, were flown to Medstar Washington Hospital Center, Mayor Muriel E. Bowser tweeted at about 1:45 p.m.

At a press conference Monday afternoon at Medstar Washington Hospital Center, interim D.C. Police Chief Peter Newsham said the officers, the driver they tried to help and the driver of the vehicle that hit them all were hospitalized with non-life-threatening injuries.

Though D.C. police initially reported that the driver of the vehicle the officers stopped to assist had experienced a medical emergency, why the vehicle stopped and why the other vehicle struck the officers was still under investigation, according to Newsham.

“We don’t know what caused the other vehicle to lose control,” he said.

Newsham added that the officers, veteran police officers with more than four years of service from D.C.’s Third District, were not in their patrol area, but stopped to help nonetheless.

“We want to extend a sincere appreciation for what they did,” he said.

Christine Trankiem Wall, a physician at Medstar Washington Hospital Center, said the officers and the driver they stopped to help were being treated for serious injuries to their lower extremities and would stay at the hospital overnight.

The driver of the car that struck the officers was being treated elsewhere, Newsham said, and it was not yet clear whether charges would be filed.

Police detoured northbound I-295 traffic at the 11th Street SE and Martin Luther King Avenue exit.