JAKARTA, Oct. 3 (Xinhua) -- Mount Soputan in Indonesia's North Sulawesi province spewed a column of ash up to 4 km into the sky on Wednesday, a disaster agency official said.

The volcanic ash headed westward and northwestward of the crater, spokesman of national disaster management agency Sutopo Purwo Nugroho said.

Rain of ashes is projected to fall in the northwest of the crater, and local disaster agency officials had distributed masks to the folks, the spokesman noted.

An exclusion zone has been declared 4 km from the crater and extended to 6.5 km for the areas situated in the southwest of the crater by the country's volcanology agency, Sutopo said.

Residents living near rivers whose upstream are around the flank of the volcano are warned to exercise caution, particularly during rain, for the risk of fast-moving flows of cool lava, the spokesman told Xinhua in a text message.

North Sulawesi province is located next to Central Sulawesi province which is reeling from the risks of powerful quakes that triggered tsunami on Friday, leaving over 1,249 people dead.