The National Weather Service extended a “red flag” warning until 6 p.m. today for all leeward sections of the Hawaiian islands because of strong trade winds and low humidity, indicating the potential for widespread brush fires.

Honolulu Fire Department Capt. Terry Seelig, said a “red flag” warning means “there is a greater potential now” for a brush fires in Leeward Oahu because of the weather conditions.

He asked that the public be cautious and immediately report fires and suspicious activities.

The National Weather Service has said low rainfall, low humidity and sustained wind speeds of more than 20 mph, as measured at Honolulu Airport, are the criteria for a red-flag warning. Low humidity means fires will burn hotter and faster.

Yesterday, a brush fire on Maui burned about 25 acres and disrupted traffic.

The fire was first reported yesterday afternoon in the Kahului area. Heavy smoke and high winds closed portions of Hana Highway and Hansen Road, which were later reopened.

Fire crews from Kahului, Paia, Makawao and Wailea fought the fire, with assistance from the state Division of Forestry and Wildlife, two helicopters, and heavy equipment from Hawaiian Commercial and Sugar Company and the county.

The cause of the fire remains under investigation.