PITTSBURGH (REUTERS) - At least six people were stabbed in an attack at a Pennsylvania high school on Wednesday morning, according to local media reports.

The stabbings occurred at Franklin Regional High School in Murrysville, about 20 miles east of Pittsburgh, Pittsburgh's WTAE and other local news channels reported, citing the emergency management office in Westmoreland County.

Multiple ambulances were seen at the school which is in a lockdown mode, reports said.

Four victims were flown to hospitals. A doctor interviewed at the scene said four victims had "significant" injuries and two of them were "in a bad shape".

The stabbings happened in a classroom and hallway, just as the school opened.

A male student is a suspect and is believed to be in custody.