Maui firefighters are battling a brush fire on the southern slopes of Haleakala that has scorched about 25 acres.

The fire, first reported at 5:11 a.m., was 90 percent contained by 5:30 p.m. No structures are threatened and area homes are not being evacuated.

Firefighters said there was no fire on the perimeter and firefighters would patrol the area overnight.

Piilani Highway, closed between mile post 24.5 and 26, was later reopened.

Firefighters from Kula were first to arrive on scene at about 5:51 a.m. The blaze was about 80 percent contained at about 9 a.m., fire officials reported.

The cause is unknown.

Battling the brush fire are five companies and three water tankers from Kula, Makawao, Kahului, Wailea, and Lahaina. Two helicopters are providing water drops. Additional crews have been called back to work and about 27 firefighters are on the scene.