JAKARTA, Sept. 26 (Xinhua) -- The number of evacuees has risen to more than 57,000 as a volcano in Bali resort island is potential to erupt, a senior official of disaster agency said on Tuesday.

That compares to over 48,000 as of Monday as seismic activity of Gunung Agung in Karang Asem district is continuously increasing.

Indonesia has raised the alert level to the highest for the Gunung Agung volcano.

"Volcanic activities keep rising as movement of magma to the surface has been more intensive," Sutopo Purwo Nugroho, spokesman of national disaster management agency told Xinhua in a text message.

Frequency of deep and shallow volcanic tremors, and tectonic tremors have increased, he added.

President Joko Widodo is to visit the displaced persons at evacuation centers on Tuesday, the official said.