A volcano has erupted in central Indonesia, in the same area devastated by an earthquake and tsunami that has left at least 1,407 people dead.

Hundreds are injured and others still trapped in the debris on the island of Sulawesi following the disaster four days ago, and now authorities have issued a warning about volcanic ash in the air.

Mount Soputan in North Sulawesi province spewed ash nearly 20,000ft into the sky.

The eruption status has been raised from an alert to “standby” 2.5 miles from the summit and up to four miles to the west-south-west.

Four days after the earthquake and tsunami disaster, teams are still searching for trapped survivors under destroyed homes and buildings, but they need more heavy equipment to clear the rubble.

Much of the attention so far has focused on the biggest affected city in the area, Palu, but thousands of people in outlying areas are still waiting for assistance which cannot get to them due to blocked roads, while downed power and phone lines are making communication difficult.

Sulawesi has already been devastated by an earthquake and tsunami Credit: AP

“Standby” status means people should avoid the area nearest the volcano and have masks available in the event of ashfall.

Planes were warned of the ash clouds because volcanic ash presents a hazard for plane engines.

Soputan is on the northern part of Sulawesi island, where a central region was severely damaged by an earthquake and tsunami on Friday.

Indonesia has dozens of active volcanoes.

Palu bridge before and after the tsunami. Credit: AP Credit: PA