The eruption of a volcano on the Indonesian island of Bali for the second time in a week spurred the evacuation of at least 24,000 people and the cancellation of scores of flights this weekend as a plume of ash and steam spewed more than 19,000 feet into the sky.

On Monday, Indonesia’s National Board for Disaster Management raised its alert for the volcano, Mount Agung, to the highest level possible, and said in a statement that a “potential for a larger eruption is imminent.” An evacuation area was extended to six miles around the volcano.

International airlines canceled flights Saturday and Sunday to and from the island, which is popular with tourists, after Mount Agung erupted around 5:30 p.m. Saturday.