A fire started aboard an in-service MTA bus near Grand Central Station early Thursday, officials said.

The blaze erupted on the M101 bus on Lexington Avenue near East 45th Street around 6:40 a.m., and was under control by 7:40 a.m., fire officials said.

No passengers were aboard at the time and no one was hurt, officials said.

But there were plenty of frayed nerves.

“NYC bus explosion next to Grand Central Station. Windows blown out on both sides,” Twitter user @MichaelAnthy tweeted alongside photos of the bus.

The images show blown-out windows and shattered glass on the ground. The back of the bus appeared to suffer the most damage, with seats burned to a crisp.

It was not immediately clear how the fire started.