Seven Indonesian airports – including two serving Jakarta – remained closed on Monday ⁠morning because of volcanic ash from eruptions at Mount ⁠Anak Krakatau, the transport minister ⁠said.

Ash from ​Anak Krakatau, which sits halfway between Java and Sumatra islands, has blanketed Jakarta and several surrounding areas since it erupted ⁠late on Friday, leading to the closure of the airports for safety reasons.

The transport ministry said 170,000 people have been affected by flight ⁠cancellations.

The suspension at Jakarta’s main airport was extended until 6pm Monday local time, along with six other airports, the airport authority said. The airports include ones serving Jakarta’s nearby provinces of Lampung and West Java.

“We ‌cannot ascertain when this ‌will end due to the dynamic weather,” the transport minister, Dudy Purwagandhi, said.

“To date, 1,558 flights have been delayed at the eight affected airports, with 170,000 passengers stranded,” the ministry said in a statement on Sunday. More than 900 affected flights were to and from the Soekarno-Hatta, it added.

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Schools across Jakarta were also affected with classes moving online on Monday, the city said in a statement, without specifying how long the measure would be in place.

Some shipping has also been disrupted.

Eruptions of Anak Krakatau on Saturday produced a fountain of lava and booming sounds that could be heard up to a few hundred kilometres away, the geology agency said.

There were more eruptions on Sunday, with the volcano monitoring agency’s website showing the most recent occurring on Sunday at 8.23pm.

The agency warned on Monday that “the probability ‌of further eruptions in the coming periods remains high”.

Ash from the volcano was detected in the airspace surrounding Soekarno-Hatta international airport, prompting authorities to suspend operations, the ministry said.

The disruption left some passengers scrambling to find alternative flights.

Passengers queue at check-in desks as flights are cancelled at Jakarta’s Soekarno-Hatta International Airport because of ash from the Anak Krakatau volcano. Photograph: Faisal Ramadhan/EPA

Henny Yensan, 44, who had hoped to go back to her home town with her mother, said “everybody was disappointed”.

“No one flew into a rage because, after all, this is due to natural disaster,” the businesswoman who had to reschedule her flight to Tuesday told AFP.

Volcanic ash also reached the city of Bandar Lampung in the southern tip of Sumatra, blanketing parked cars and roadsides.

Anak Krakatau, which means Child of Krakatau, sits in a strait that separates the islands of Java and Sumatra.

Ships passing through the strait were asked to increase vigilance for possible disruption to navigation safety due to volcanic activities.

Vessels are prohibited from approaching an exclusion zone of a 3km radius from the volcano, local port authorities said in a statement.

The volcano has been sporadically active since it emerged from the sea at the beginning of last century in the caldera that formed after the 1883 eruption of Mount Krakatau.

That disaster was one of the deadliest and most destructive in history with an estimated 35,000 people killed.

Geology agency head Lana Saria warned against approaching Anak Krakatau, saying materials ejected from the volcano could endanger those within the exclusion zone.

She said the most recent series of eruptions do not have the potential to trigger a tsunami.

A 2018 tsunami triggered by a collapse of parts of Anak Krakatau killed 429 people and left thousands displaced.

Indonesia, a South-east Asian archipelago nation, sits on the Pacific Ring of Fire, where the meeting of continental plates causes high volcanic and seismic activity.

With Reuters