Ash spewing from a rumbling volcano in eastern Indonesia has forced closure of two airports and international airlines canceled flights to tourist hotspot Bali, stranding thousands.

The National Disaster Mitigation Agency spokesman Sutopo Purwo Nugroho says the eruption of Mount Rinjani volcano on the tourist island of Lombok, about 135 kilometers (84 miles) from Bali's international airport, has increased in the past days, and on Wednesday it blasted ash and debris 3,500 meters (11,480 feet) into the air.

He says the eruption forced authorities to close Selaparang airport in Lombok and Ngurah Rai airport in Bali due to the risks posed by volcanic ash.

The Transportation Ministry has told airlines to avoid routes near the mountain.

A decision about reopening the two airports would be made early Thursday.