A fire burned about 25 acres Saturday in the Nestor neighborhood near Tijuana River Valley Regional Park, authorities said.

The blaze began about 1:45 p.m, on Wardlow Avenue and International Road in an area of mostly grass and brush, said Maurice Luque, spokesman for the San Diego Fire-Rescue Department.

The area is southeast of Interstates 5 and 905, and the California Highway Patrol reported smoke could be seen from the freeways.

About 50 firefighters responded, including personnel from Chula Vista, as
well as two water-dropping helicopters from the Sheriff's Department.

"They caught this fire very quickly," Luque said.

There were some structures nearby, but they were never seriously threatened, Luque said.

There were no injuries, and the cause of the blaze was not yet known, Luque said.