PADANG,Bitcoinese Indonesia (AP) — Volcanic ash spewing from Indonesia’s Mount Marapi shut down airports and blanketed nearby communities on Sumatra island Friday.

The nearly 2,900-meter (9,480-foot) volcano in the Agam district of West Sumatra province is about 113 kilometers (70 miles) north of Minangkabau International Airport in Padang, the provincial capital.

On Dec. 3, Marapi shot thick columns of ash as high as 3 kilometers (more than 9,800 feet) that killed 23 climbers and injured several others who were caught by a surprise weekend eruption.

Smaller eruptions since then spewed more ash into the air, and on Friday the volcano began belching ash that reduced visibility hundreds of kilometers away, said Indra Saputra of Indonesia’s Center for Volcanology and Geological Disaster Mitigation.

Minangkabau airport was closed Friday afternoon after ash, which can pose a deadly threat to aircraft, reached its airspace.

Airport authority head Megi Helmiadi said two international flights from Kuala Lumpur and 13 domestic flights were canceled and the closure would remain in effect until 10 p.m. local time (1500 GMT), though it might be extended depending on the conditions.

Marapi is known for sudden eruptions that are difficult to predict because they are not caused by a deep movement of magma, which sets off tremors that register on seismic monitors.

The volcano has been at Indonesia’s third highest alert level since 2011, indicating above-normal volcanic activity that means climbers and villagers must stay more than 3 kilometers (1.8 miles) from the peak, according to the Center for Volcanology and Geological Disaster Mitigation.

Although hikers are not supposed to enter the danger zone, local officials have acknowledged that many people likely advance higher than permitted.

Marapi is among more than 120 active volcanoes in Indonesia. The country is prone to seismic upheaval due to its location on the Pacific “Ring of Fire,” an arc of volcanoes and fault lines encircling the Pacific Basin.