The death toll following the tsunami caused by the Anak Krakatau volcano in Indonesia has risen to at least 429, the disaster mitigation agency says.
On Saturday giant waves crashed into coastal towns on the islands of Sumatra and Java.
It is thought that volcanic activity set off undersea landslides which in turn generated the killer waves.
About 150 people are still missing, while more than 16,000 have been displaced, the agency says.
Coastal residents near the volcano have been warned to keep away from beaches amid fears it could trigger a new tsunami.
Anak Krakatau erupted again on Sunday, spewing ash and smoke.
Video shot from a charter plane captured the magnitude of the volcanic event in the Sunda Strait, between Sumatra and Java.
Rescue efforts are being hampered by blocked roads but heavy lifting equipment is being transported to badly hit areas to help search for victims.
What warning was given?
On Monday, a spokesman for the National Disaster Management Agency told a news conference that another tsunami was a possibility because of the continued volcanic eruptions of Anak Krakatau.
"Recommendations from [the] Meteorology, Climatology and Geophysical Agency are that people should not carry out activities on the beach and stay away from the coast for a while," said spokesman Sutopo Purwo Nugroho.
Anak Krakatau, which emerged in 1927 from the caldera that was formed during the eruption of Krakatoa in 1883, has seen increased activity in recent months with people asked to avoid the area around its crater.
On Monday Mr Sutopo put out a series of tweets explaining why there was no early warning for this tsunami. He said that Indonesia's early warning system is set up to monitor earthquakes but not undersea landslides and volcanic eruptions, which can also generate deadly waves.
But, he added, with 13% of the world's volcanoes in Indonesia alone, it was crucial for the country to develop such system.
He confirmed there was no tsunami advance warning system on the night of the disaster, adding that because of lack of funds, vandalism to the buoys and technical faults there had been no operational tsunami warning system since 2012.
Geologist Raphaël Paris, whose 2012 study predicted the collapse of a flank of Anak Krakatau and a subsequent tsunami, said: "There is a big uncertainty on the stability of the volcanic cone now, and the probability for future collapses and tsunamis is perhaps non-negligible."/BBC