SAN DIEGO -- A 21-year-old man was killed Friday when he crashed his motorcycle on a Mira Mesa street at high speed, authorities reported.

The man was heading east in the 10000 block of Mercy Road about 7:30 a.m. when he lost control on a curve, sending the two-wheeler veering into a raised center median, according to San Diego police.

The motorcycle then swerved off the roadway, crashed into a tree and flipped over, hurling the rider onto the ground headfirst, SDPD spokeswoman Monica Munoz said.

Medics performed CPR on the man at the scene before taking him to Sharp Memorial Hospital, where he was pronounced dead a short time later. His name was withheld pending notification of his family.

The accident forced the closure of the eastbound lanes of the thoroughfare between Black Mountain Road and Interstate 15 for several hours.

Witnesses said the motorcyclist appeared to be traveling at about 80 mph at the time of the crash, Munoz said. The posted speed limit in the area is 45 mph, she said.