Emergency crews are on the scene of an accident involving an overturned tractor trailer on the Pennsylvania Turnpike's Northeast Extension.

The accident was reported shortly before 2:30 p.m. Monday on the northbound entrance ramp to the Allentown Service Plaza.

No one was injured, said police, who did not know what the truck was hauling.

Traffic on the Northeast Extension is not reported to be affected, but northbound motorists are advised to be alert as they approach the area.