UPDATE: Multi-car pile-ups in icy conditions on interstates in the Philadelphia area have claimed at least three lives.
State police in Delaware County say three people were killed in a crash involving multiple vehicles in the southbound lanes of Interstate 476 on Sunday morning.
Another pileup involving 30 to 50 vehicles that shut all lanes of Interstate 76 west of Philadelphia was blamed on "flash-freezing."
The Delaware River Port Authority closed bridges linking Philadelphia and New Jersey while workers put down more salt, but began reopening lanes by midmorning.
Pennsylvania Department of Transportation spokesman Eugene Blaum called travel conditions "very hazardous."
PennDOT said at least 14 accidents were reported on the region's major highways.
The Southeastern Pennsylvania Transportation Authority canceled early bus service in Philadelphia but planned to resume service as of 11 a.m. Sunday.
PHILADELPHIA (AP) — Icy conditions and accidents have closed highways and bridges in and around Philadelphia, including a pileup involving at least 20 cars on a major artery that serves the city's western suburbs.
Interstate 76 is closed in both directions after a series of cars slammed into one another amid freezing rain Sunday morning. The accident occurred before 7 a.m. in the westbound lanes near the Gulph Mills exit. The extent of any injuries was unclear.
This is the view above I-76 at Gulph Mills. Please stay off the roads if you can. pic.twitter.com/q8YH4Ua0hd— Josh Shapiro (@Josh_Shapiro) January 18, 2015
Long lines of stopped traffic I-76 eastbound near King of Prussia PA per Web cam image pic.twitter.com/gnhsF0iYUp— Matt Sutkoski (@mattalltradesb) January 18, 2015
Accidents caused the closure of Interstate 95 in both directions in parts of Philadelphia, and all four bridges linking the city and New Jersey were closed as workers applied salt.
Messages left with the transportation department and state police were not immediately returned.
A freezing rain advisory is in effect in the area through 10 a.m. but temperatures were forecast to rise into the 40s later Sunday.