Hundreds of people fled their homes in the Philippines on Wednesday after a volcano spurted harmful gases, an official said, as experts warned of a potential eruption.

About 300 residents of villages within four kilometres (2.5 miles) of the Kanlaon volcano crater in the centre of the country were evacuated on Tuesday as a precaution, the local government of nearby Canlaon City said.

The evacuees have taken temporary shelter at schools and community centres away from the volcano, city information officer Edna Lhou Masicampo told AFP on Wednesday.

"People from villages near the foot of the volcano have been complaining about the strong smell of sulphur," Masicampo said, adding most of the residents were farmers.

Classes were suspended and some tourist spots in the city of around 60,000 people were closed on Wednesday due to the volcano warning.

Kanlaon's daily average emission of sulphur dioxide almost tripled to 9,985 tonnes on Tuesday.

"This is the highest emission from the volcano recorded since instrumental gas monitoring began," the Philippine Institute of Volcanology and Seismology said in a statement.

"Current activity may lead to eruptive unrest," it added, putting residents of the four villages at risk from red hot, swiftly moving ash clouds, "ballistic projectiles, rockfalls" and other hazards.

The area was rocked by 337 volcanic quakes in the past 24 hours, the institute said in a later update, which also included photos and videos of plumes rising 1,000 metres (3,280 feet) into the sky from the volcano's peak.

Rising more than 2,400 metres above sea level on the central island of Negros, Kanlaon is one of 24 active volcanoes in the Philippines.

It has erupted 15 times in the past nine years.

Three hikers were killed in August 1996 due to ash ejection from Kanlaon.

The state volcanology agency raised the alert level for the volcano in June from one to two on a zero-to-five scale, warning more explosive eruptions were possible.

The Philippines is located in the seismically active Pacific "Ring of Fire", which contains more than half the world's volcanoes.

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