At least four people were wounded in a shootout Monday in Birmingham, Alabama, where gunshots apparently hit a city transit bus, according to reports.

Two groups of gunmen opened fire outside the bus, which was hit by several bullets and left three people wounded. The identities of the victims have not been released, but the Birmingham Police Department said two of the victims were male and one was female.

It was unclear if any of the victims had been passengers aboard the bus.

One of the gunshot victims was in critical condition and three others were stable after being transported to local hospitals, reports said.

One unidentified suspect was taken into custody after trying to flee the scene. A Birmingham police officer opened fire during the pursuit, and a second suspect was still at large, reports said.

The shooting erupted late Monday afternoon near the 3300 block of Fred L. Shuttlesworth Drive and 33rd Street North, where police received a call about a person who was shot and wounded outside and then boarded a MAX Transit bus.

The public transportation agency reported gunfire struck the bus.

The driver and an unknown number of other passengers were reported safe.

The circumstances of the shooting were unclear, and authorities did not provide additional information.

This is a breaking news development. Please stay with AJC.com for the latest details.