Six people are dead after a school bus and a commuter bus crashed in Baltimore Tuesday morning, police said.

The crash happened in the 3800 block of Frederick Avenue around 6:30 a.m., according to Baltimore police.

Police spokesman T.J. Smith said the crash occurred when the bus slammed into a car, hit a pillar and then crashed into an MTA bus. Both drivers died. The school bus was driven by a 67-year-old man. The MTA bus was driven by a 33-year-old woman. Four passengers on the commuter bus were killed. Ten other people were injured, Smith said.

There were no children on the bus when the tragedy occurred, Smith said. The school bus was two blocks away from picking up the first child of the morning.

Smith said a second person on the bus, an aide, survived and might be able to provide more information to investigators. He said there were no skid marks on the road, indicating the school bus driver may not have attempted to break.

Authorities have video and data recorders from one or both vehicles.

A medical examiner will attempt to determine if the school bus driver suffered a medical emergency prior to the crash, Smith said. He declined to provide further details on the victims.

"We have six families that we have to notify that their loved ones aren't coming home," Smith said.

Other people suffered injuries as a result of the crash. One victim is in critical condition, one in serious condition and two are in fair condition at UMD Medical Center, hospital officials said. One patient has been discharged. The five patients treated at UMD Medical Center range in age from mid-20s to mid-40s.

The road is currently closed in the area.