A brush fire off the side of northbound Interstate Highway 280 near Belmont burned approximately 15 acres this afternoon, a Cal Fire spokesperson said.

The fire was reported shortly before 10 a.m. near the I-280 and state Highway 92 interchange, west of Belmont, according to the California Highway Patrol.

Two lanes were shut down while fire crews battled the blaze, a CHP dispatcher said, adding that they are expected to reopen at 5 p.m.

Roughly 45 Cal Fire firefighters, along with an aircraft, battled the blaze and had it 50 percent contained around 1 p.m. Friday, Cal Fire spokesperson Lynne Tolmachoff said.

Tolmachoff said firefighters stopped the forward spread of the fire and were working to mop up any hot spots.

No structures were involved in the fire and no injuries were reported, she said.