PHILADELPHIA (CBS) — A serious accident involving numerous vehicles shut down a stretch of the Pennsylvania Turnpike for several hours Saturday in Chester County.

It happened around 10 a.m. Saturday in the eastbound lanes approaching Downingtown.

Drivers at the scene of the crash told the KYW Traffic Center it appeared that more than 20 vehicles were involved.

All eastbound lanes were blocked for more than four hours as a result of the pile-up.

Officials said at least nine people were taken to Paoli Hospital, where they were treated and released.

There was no other word on injuries.

The accident happened just two hours after another crash involving at least 20 vehicles brought all traffic to a halt along the Schuylkill Expressway (I-76) in Montgomery County.