Six people have died after a school bus and commuter bus crashed early Tuesday in Southwest Baltimore, police said.

No students were on the school bus during the crash, police said.

T.J. Smith, a police spokesman, said the incident occurred in the 3800 block of Frederick Avenue before 7 a.m.

Smith said the driver of the school bus and five people on the MTA bus were killed after the school bus, which was headed east, hit a Ford Mustang and a pillar on the side of the road before entering oncoming traffic and ripping through the driver’s side of the MTA bus.

“It literally looks like a bomb exploded in the bus, and it’s catastrophic damage,” Smith said of the MTA bus.

In addition to the dead, at least 10 people were injured, including an aide on the school bus, eight people on the MTA bus and the driver of the Mustang, Smith said. Their injuries ranged from minor to critical, he said.

He said he did not have any information on the identities of the dead and injured, including their ages.

Police Commissioner Kevin Davis said it was a “complicated scene” and that it is “going to take a lot of resources to get to the bottom of what happened.” He said emergency officials would be on the scene throughout the day.

“It’s important to keep the families in mind and the folks who lost their lives,” Davis said.

The University of Maryland Shock Trauma Center received four people in fair condition and one person in critical condition, spokeswoman Lisa Clough said.

Baltimore Fire Chief Niles Ford said the scene was unlike anything that his seasoned first responders had ever seen before, and that emergency crews were still trying to access certain areas within the crash scene.

“There are still portions of the bus that our people have not been able to fully access,” he said in a morning briefing.

Smith said the killed driver and the injured aide were the only two people on the school bus at the time of the crash. There are believed to have been 13 people on the MTA bus at the time, he said.

Smith said officials “can’t speculate on the cause” of the crash. “It is not a crime scene. It’s a crash investigation scene,” he said.

“It is a pretty horrific scene,” he said.

He did not know when the road would be reopened to traffic, and asked for patience from the community as first responders do their “due diligence for the families of the victims.” Drivers are asked to take alternate routes.

Smith said he did not know if speed was a factor in the crash, but noted “there aren’t any skid marks, so something catastrophic took place.”

Smith said police hope to be able to interview the surviving aide on the school bus about what occurred just prior to the crash.

The force of the collision shook nearby Loudon Park Cemetery, said Superintendent Matt Wagster.

“It sounded like a train wreck,” he said. “It was loud and it shook the ground.”

Kevin Travers, 55, a maintenance worker for St. Joseph’s Monastery nearby, said he’d walked past the scene of the crash just before it happened.

He went inside the maintenance building at Frederick Avenue and South Morley Street about 6:15 a.m., and then heard the police helicopter overhead when he took the recycling out 15 minutes later.

“It happened real fast,” Travers said.

Mary Schruefer, 60, an administrator at Mountain Manor Treatment Center, a drug addition counseling facility at the monastery, peered down at the crash scene from a side road.

“That’s horrible,” she said. “It just opened up the side of the bus.”

Lori Shannon, 54, a staff accountant at the treatment facility, said she had to take a detour onto Wilkens Avenue on her way into work due to the road closure. A coworker called her and told her about the fatal accident.

“It’s shocking to see this,” Shannon said.

The scene is about two blocks from Mount St. Joseph High School. The school opened an hour late Tuesday for All Saints Day, and the opening was not delayed further, school officials said.

Baltimore schools spokeswoman Edie House Foster said the bus was contracted for the city school system. She could not immediately say early Tuesday which school the bus was for.

City Councilwoman Helen Holton said she was awaiting information about the accident, which occurred in her district.

“I’m just devastated — period,” the longtime councilwoman said. “The fact that a school bus and MTA bus were involved, it is just tragic, horrific.

“Families will be destroyed out of this, people going about their normal routines. At this hour, if you’re on the bus, you’re going to work or school.”

Gov. Larry Hogan issued a statement on the crash:

“The First Lady and I are deeply saddened to hear of the horrific crash this morning in Southwest Baltimore involving a school bus and an MTA commuter bus. Our deepest condolences go out to the victims and their families in the wake of this tragedy. We will continue to pray for those who were injured, as well as the first responders who worked swiftly and continue to care for the injured.

“Our administration gives our full support to the Baltimore City Police Department as they investigate, and we are prepared to offer any state assistance necessary.”