A crash involving an MTA bus in Brooklyn Wednesday left nine injured — one critically, officials said.

A blue Mercury Grand Marquis and gray Lexus RX 300 collided with an MTA bus just after 1:45 p.m. at Clarendon Road and Utica Avenue in East Flatbush, according to the FDNY.

The front end of Grand Marquis had significant damage and the windshield was smashed in — while pools of blood were visible on the passenger seat.

One of the drivers was seriously injured and rushed to King County Hospital. It was unclear which car the person was driving, police said.

Five others were taken to King County Hospital for treatment for minor injuries.

Three were treated on the scene.

Rudolph Fraser, 80, told a Post reporter his wife, Renee, was driving the Lexus.

“My wife was in that car. She’s in the hospital. We don’t know if she has any broken bones.”

BP gas station manager Michael Johnson said he saw the accident unfold and heard people screaming.

“I’ve seen two cars collide and spin. Everyone rushed the blue car because he was the more injured one.”