Jakarta, Nov 28 : Indonesia's Anak Krakatau volcano located in the waters of the Sunda Strait erupted on Tuesday, spewing an ash cloud of about 1 km high, an official said.

The volcano's Observation Post Officer Anggi Nuryo Saputro said the eruption occurred at 6.29 a.m. for 130 seconds, with the wind heading north, reports Xinhua news agency.

"The ash column was observed to be gray to black in colour with thick intensity towards the north," he said in a statement.