A fire fighter sprays water to extinguish a forest fire in Pekanbaru, Riau province, Indonesia (Source: http://abcnews.go.com)

Jakarta (VNA) – Indonesia has declared emergency in anticipation of worsening forest fires in Riau and South Sumatra provinces on Sumatra Island and West and Central Kalimantan on Borneo Island.

It was estimated that hundreds of hectares of forest have been burned in the localities. Authorities have been making efforts to extinguish the fires.

Spokesman of Indonesia's National Disaster Mitigation Agency Sutopo Purwo Nugroho said its personnel as well as soldiers, police, businesses and volunteers were involved in the fire-fighting efforts.

Satellites have detected 90 "hotspots" of fires across Indonesia, with the most in West Kalimantan, he added.

Forest fires occur frequently in Sumatra and Borneo islands during the dry season. In 2015, about 2 million ha of forest were razed, resulting in toxic dust affecting neighbouring countries Singapore and Malaysia.

A study carried out by US scientists showed the catastrophe may have caused over 100,000 premature deaths.-VNA