OAKLAND — Five separate fires in Dimond Canyon below Park Boulevard — including two that sent 30-foot flames into the air and provoked a heavy response — were being investigated as suspicious Tuesday afternoon.

A pair of brush fires in the deep and wooded canyon that is surrounded by million-dollar homes quickly went to four alarms Tuesday afternoon, but both were contained in less than an hour, Oakland fire officials said.

No one was injured and no structures were damaged.

The first blaze was reported at 1:56 p.m. near the intersection of Park Boulevard and Estates Drive, according to Oakland fire Battalion Chief Lisa Baker. Crews arriving on the scene minutes later spotted the second fire, which was about a half-mile north of the first, she said.

Both fires were hundreds of feet down the steep canyon. Once the blazes were contained shortly before 3 p.m., three more canyon small fires, all of which burned 10-by-12 foot patches of grassland, were discovered by crews in the area and quickly controlled, Baker said.

“Our fire investigators are looking at these fires as suspicious,” she said.

The first fire reported burned about 2½ acres, Baker said; the second fire to the north consumed roughly 3 acres.

Crews sprayed water at the blazes from roads above the canyon, California Department of Corrections inmate firefighters hiked into the canyon to assist with fire control and CalFire helicopters dropped water.

Park Boulevard was closed between Monterey and Leimert boulevards for hours and water was pulled from Lake Merritt to quell the fires. Firefighters laid fire hose through the western end of the Montclair Golf Course so they could reach the flames.

Firefighters took no chances Tuesday as the fires were just two miles from the ignition point of the 1991 Oakland Hills firestorm. That wind-whipped fire spread quickly from the hills toward the canyons, killing 25 people and destroying 3,400 homes.

“Our concern was the high power lines (over the area of the fire) because at one point we had flames about 30 feet in the air,” Baker said.

Both of the larger fires Tuesday were contained around 2:45 p.m., Baker said, but dozens of residents and motorists stopped to watch fire crews battle the blazes.

“We just smelled the smoke, (then) we heard the helicopters and the sirens,” said resident Jamie Barr, 18, who lives about two blocks from the more southern fire. “Once we walked to the Leimert (Boulevard) bridge, we saw tons of smoke.”

Barr added that he had seen another fire in the same area three days ago.

Staff writers Matt O’Brien and Rick Hurd contributed to this story.