(This version of the story corrects number of troops in paragraph 1 to 1,000 from 10,000; headline altered to reflect change)
PADAMARAN, Indonesia (Reuters) - Indonesia said on Friday it will send more than 1,000 troops to fight fires in southern Sumatra, as smoke makes thousands sick, delays flights and pushes air quality to unhealthy levels in neighboring Singapore and Malaysia.
Indonesia has vowed before to end the seasonal fires but has failed each time to stop the so-called "haze", caused by slash-and-burn clearances on the islands of Sumatra and Borneo, where large areas of forest concessions are held by pulp and paper and palm oil companies.
Indonesian troops will be sent to the provinces of South Sumatra and Jambi, two of the main hotspots, Indonesia's National Disaster Mitigation Agency (BNPB) said.
If necessary, the agency would also send in additional helicopters to help water-bomb fires.
"We have mobilized national resources to put out the fires," newly appointed BNPB chief Willem Rampangilei said in a press release.
South Sumatra, one of the main centers of the fires, has alone reported 22,585 cases of acute respiratory tract infections since Friday.
Early on Friday, Singapore's Pollutants Standard Index rose to 248, which categorizes the air as "very unhealthy", or one level below the index's highest air pollution category of "hazardous".
Singapore, which was voting in a general election on Friday, advised citizens against strenuous outdoor exercise.
(Reporting by Beawiharta and Heru Asphiranto; Editing by Nick Macfie)