The alert level for Indonesia's Anak Krakatau volcano has been raised to the second-highest level possible, after a series of eruptions. All flights around the volcano have been rerouted and a 5km (three-mile) exclusion zone has also been imposed, reports BBC.

Indonesia's disaster management agency (BNPB) said the alert level had been raised from level two to three because of the increased volcanic activity.

Last Saturday, the volcano triggered a tsunami which killed hundreds.