Indonesia's Mount Bromo spews ash

Indonesia's Mount Bromo is spewing volcanic ash more than a kilometre high, forcing the closure of an airport.

Commercial flights to Abdulrachman Saleh airport in the city of Malang were diverted to an international airport in Surabaya.

Mount Bromo, in East Java province, began ejecting ash and thick smoke on April 1.

Indonesia's volcanology agency had raised its alert level on the mountain to 2, on a scale of 1 to 4, in February.

The agency recommends tourists stay out of a 1km radius from the site.

Mount Bromo is a popular tourist destination in Indonesia, and its increased volcanic activity has forced the closure of airports in the East Java and Bali region several times since December.

"There were five flights scheduled to operate this morning but four were cancelled," a Malang airport spokesman was quoted as saying by Viva.co.id news site on Sunday.