JAKARTA, Aug. 3 (Xinhua) -- Anak Krakatau volcano in Indonesia's Sunda Strait has erupted with seven explosions in the last two days, unleashing hot ash by up to some 1,500 meters high into the sky, Indonesia's Meteorology, Climatology and Geophysics Agency (BMKG) said on Wednesday.
"The volcano is currently graded at level three of a four-tiered volcanic alert system," the agency said in a press release.
The seismic activity of the volcano has increased since two weeks ago, according to the BMKG. The authorities have ordered people to stay out of a five-kilometer exclusion zone around the volcano.
Anak Krakatau, which means Child of Krakatau, has been sporadically active since it emerged from the sea at the beginning of last century.
The volcano is located far from the densely-populated Java island and Sumatra island. However, it is near the busy shipping line connecting the islands.