KONTAN.CO.ID - JAKARTA. Indonesia on Thursday rerouted all flights around the erupting Anak Krakatau volcano between Java and Sumatra islands, as it spewed columns of ash into the air, days after it triggered a deadly tsunami.

A crater collapse on the volcanic island at high tide on Saturday sent waves up to 5 meters (16 feet) high smashing into the coast on the Sunda Strait, leaving at least 430 dead and hundreds more missing.

“All flights are rerouted due to Krakatau volcano ash on red alert,” the government air-traffic control agency AirNav said in a release.

Authorities raised the volcano’s alert level to the second-highest on Thursday, imposing a 5-km exclusion zone.

Indonesia's Disaster Management Agency (BNPB) said the alert level had been raised from level two to three - the second-highest level possible.

Last Saturday, the volcano triggered a tsunami which killed hundreds. "The volcanic activity of Anak Krakatau continues to increase," said BNPB in a press statement, citing data from the Volcanological Survey of Indonesia.

"At present, eruption activity is still ongoing. The danger zone [has been] extended from 2km to 5km... people and tourists are prohibited from carrying out activities with a 5km radius."

Indonesia is prone to tsunamis because it lies on the Ring of Fire - the line of frequent earthquakes and volcanic eruptions that circles virtually the entire Pacific Rim.

Editor: Wahyu T.Rahmawati