TAGAYTAY, Philippines (AP) — A small volcano south of the Philippine capital that draws many tourists for its picturesque setting in a lake erupted with a massive plume of ash and steam Sunday, prompting thousands of people to flee and officials to shut Manila’s international airport.

The Philippine Institute of Volcanology and Seismology said Taal Volcano in Batangas province south of Manila blasted steam, ash and pebbles up to 10 to 15 kilometers (6 to 9 miles) into the sky in a dramatic escalation of its growing restiveness, which began last year.

The volcanology institute raised the danger level around Taal three notches on Sunday to level 4, indicating “a hazardous eruption may happen within hours or days,” said Renato Solidum, who heads the volcanology institute. Level 5, the highest, means a hazardous eruption is underway and could affect a larger area.

There were no immediate reports of injuries or damage, but authorities scrambled to evacuate more than 6,000 villagers from an island in the middle of a lake, where the volcano lies, and tens of thousands more from nearby coastal towns, officials said.

“We have asked people in high-risk areas, including the volcano island, to evacuate now ahead of a possible hazardous eruption,” Solidum said.

Renelyn Bautista, a 38-year-old housewife who was among thousands of residents who fled from Batangas province’s Laurel town, said she hitched a ride to safety from her home with her two children, including a 4-month-old baby, after Taal erupted and the ground shook mildly.

“We hurriedly evacuated when the air turned muddy because of the ashfall and it started to smell like gunpowder,” Bautista said by phone.

International and domestic flights were suspended Sunday night at Manila’s international airport “due to volcanic ash in the vicinity of the airport” and nearby air routes, the Civil Aviation Authority of the Philippines said.

Taal lies more than 60 kilometers (37 miles) south of Manila.

The institute reminded the public that the small island where the volcano lies is a “permanent danger zone,” although fishing villages have existed there for years. It asked nearby coastal communities “to take precautionary measures and be vigilant of possible lake water disturbances related to the ongoing unrest.”

Heavy to light ashfall was reported in towns and cities several kilometers (miles) from the volcano, and officials advised residents to stay indoors and don masks and goggles for safety. Motorists were hampered by poor visibility, which was worsened by rainy weather.

Hotels, shopping malls and restaurants line an upland road along a ridge overlooking the lake and the volcano in Tagaytay city, a key tourism area that could be affected by a major eruption.

Authorities recorded a swarm of earthquakes, some of them felt with rumbling sounds, and a slight inflation of portions of the 1,020-foot (311-meter) volcano ahead of Sunday’s steam-driven explosion, officials said.

Classes in a wide swath of towns and cities were suspended Monday, including in Manila, to avoid health risks posed by the ashfall.

One of the world's smallest volcanoes, Taal is among two dozen active volcanoes in the Philippines, which lies along the so-called Pacific “Ring of Fire,” a seismically active region that is prone to earthquakes and volcanic eruptions.

About 20 typhoons and other major storms each year also lash the Philippines, which lies between the Pacific and the South China Sea, making it one of the world’s most disaster-prone countries.

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Gomez reported from Manila. Associated Press journalists Francisco Rosario and Bogie Calupitan contributed to this report.