SAN FRANCISCO -- Three lanes of traffic were briefly blocked on the westbound Bay Bridge after a motorcycle was involved in a crash Friday morning, officials said.

The crash was reported about 6:30 a.m. just west of Treasure Island.

It was not clear how many other vehicles were in the crash, according to California Highway Patrol Officer James Evans. Witnesses told the CHP that the motorcycle had struck an object that had fallen off a truck in front of it, but Evans said he could not confirm that.

As many as three lanes were blocked around 7 a.m. while authorities responded to the crash site, but all lanes were reopened and traffic was moving by about 7:20 a.m.

Contact Daniel M. Jimenez at djimenez@bayareanewsgroup.com. Follow him at Twitter.com/DMJreports.