An overturned tractor-trailer is blocking a Pennsylvania Turnpike exit ramp in Upper Merion.
Montgomery County dispatchers said the accident on the westbound ramp at exit 326, Valley Forge, was reported at about 7:15 a.m.
Images from television news choppers showed an overturned tractor-trailer sprawled across the road on the ramp to the Valley Forge Interchange.
A dispatcher said initial reports indicated someone was trapped, but no other information was available about any injuries.
Officials said westbound entry and exit ramps are shut down. Motorists are advised to expect delays and use alternate exits.
The accident has snarled traffic for three to four miles at the crash site, police said. Backlogs at the next turnpike exit at Route 29 in Chester County are also reported.