A crash involving a FedEx truck and another vehicle has all lanes blocked on the westbound 10 Freeway in Pomona early Monday morning.
The crash was reported around 4:15 a.m. just east of the 57 Freeway, according to the California Highway Patrol.
The extent of any injuries resulting from the crash was not immediately known.
A SigAlert announcing the closure of all westbound lanes was issued a short time later.
Motorists on the westbound 10 Freeway were being diverted onto the 57 Freeway as crews worked to clean up oil that spilled onto the roadway.
Sky5 over the scene at 5:30 a.m. reported traffic was backed up for 2 to 3 miles on the westbound side of the freeway.
It was not clear how long the SigAlert would remain in place.
Check back for updates on this developing story.