JAKARTA, Feb. 26 (Xinhua) -- Indonesia has engaged aircraft, troops and volunteers to curb the fire that has razed forest and plantation areas in several regencies in Sumatra's Riau province, a local official said Tuesday.

Head of provincial disaster mitigation office Edwar Sanger said areas gutted by fire since last month has reached 1,136 hectares.

Edwar said most of the hotspots were detected in Riau coastal regencies of Dumai, Bengkalis, Rokan Hilir, Rupat Island and Indragiri Hilir.

"We are engaging our maximum capacity to extinguish fires in those spots at present," he added.

Due to the thickening smoke haze in Rupat island, schools are closed as of Tuesday as the visibility has worsened to 100 meters at present, he said.

Head of Riau provincial Public Health Service Dr. Yohanes said the nunber of residents who suffered from respiratory and diseases related to the forest and plantation fire since January have reached 1,753 as of Sunday.

"We give them additional dietary such as biscuit to strengthen their resiliencies," he said earlier.

To curb the raging fire in Riau province, Indonesian air forces has sent a Casa 212 plane tasked to create artificial rain to help extinguish the fire.

Indonesian military has also sent troops deployed with helicopters to the affected areas.

Forest fire is an annual man-made issue in western Indonesian provinces that host palm oil and pulp industries. Most of the fires were incited by people or plantation firms to open more land for their cultivation areas.