All flights around Indonesia's Anak Krakatau volcano have been rerouted and the alert level has been raised to the second-highest possible after a series of eruptions spewed out lava.
A five-kilometre exclusion zone around the volcano has also been imposed, the BBC reported on Thursday, December 27.
Indonesia's Disaster Management Agency (BNPB) said the alert level has been raised from two to three because of fluctuating eruptions.
"The volcanic activity of Anak Krakatau continues to increase," BNPB said, citing data from the Volcanological Survey of Indonesia.
Eruption activity is still ongoing. The danger zone has been extended from two kilometres to five kilometres... people and tourists are prohibited from carrying out activities within a five kilometre radius, it added.
According to the latest images of the devastation caused by the tsunami, there is a thin layer of volcanic ash that has settled on buildings and other items along the west coast of Java.
While authorities stated that the ash was not dangerous but residents have been advised to wear face masks and goggles when outside.
“All flights are rerouted due to Krakatau volcano ash on red alert,” the government air-traffic control agency AirNav said in a release according to Reuters.
On December 22, the volcano triggered a tsunami which hit the Sunda Strait coasts, killing over 400 hundred people while more than 22,000 are still missing.
It is believed that the volcanic activity from Anak Krakatau set off undersea landslides which in turn generated the killer waves.
The tsunami was Indonesia's third major natural disaster in six months, following a series of powerful earthquakes on the island of Lombok in July and August and a quake-tsunami in September that killed around 2,200 people in Palu on Sulawesi island, with thousands more missing and presumed dead.
On Wednesday, December 26, thousands were expected to pray for loved ones at mass graves and mosques to mark the 14th anniversary of the 2004 Boxing Day tsunami.
It was one of the deadliest disasters in history, killing some 220,000 people in countries around the Indian Ocean, including some 168,000 Indonesians, most in Aceh at the northern tip of Sumatra.
Indonesia, a vast Southeast Asian archipelago, is one of the most disaster-hit nations on Earth due to its position straddling the so-called Pacific Ring of Fire, where tectonic plates collide.