Indonesia's most volatile volcano spewed clouds of ash high into the sky Wednesday, forcing some international airlines to again cancel flights and President Barack Obama to cut short his visit.

The official death toll, meanwhile, climbed by more than 40 to 191, AP news agency reports.

Disaster officials said earlier figures had not included people who died of respiratory problems, heart attacks and other illnesses linked to the fiery mountain.

Mount Merapi, located in the heart of Java island, roared back to life two weeks ago, shooting searing clouds of gray soot and debris up to six kilometers into the air almost daily, with lava and rock cascading down its slopes.

More than 350,000 people have been evacuated to cramped emergency shelters.

Obama sliced several hours off his whirlwind 24-hour tour to Indonesia over concerns about the volcanic ash, which has been carried by westerly winds toward the capital, Jakarta. He flew to South Korea for the Group of 20 summit.

Safety concerns also prompted several international carriers to again cancel flights into and out of Jakarta, 450 kilometers from Merapi, said Syaiful Bahri, who oversees operations at the airport.

Among them were Cathay Pacific, Value Air and Qantas.

Merapi has erupted many times in the last century, killing more than 1,400. On Friday, it experienced its most explosive blast in more than a century. At least one yet-to-be evacuated village was incinerated, setting on fire houses, trees and fleeing residents.

Muhammad Anshori, a disaster official, said Wednesday the official death toll since the first eruption on Oct. 26 had climbed to 191 — up from 153 earlier in the day.

Another 600 have been hospitalized, some with burns covering 95 percent of their body.

More than 340,000 people living along its slopes and villages near the base have been evacuated, he said. They are now living in more than 80 government camps. Many complain about poor sanitation, saying the toilets and water are filthy.

Indonesia, a vast archipelago of 235 million people, is prone to earthquakes and volcanoes because it sits along the Pacific "Ring of Fire," a horseshoe-shaped string of faults that lines the Pacific Ocean.