MANILA, Jan. 13 (Xinhua) -- Nearly 50,000 people living near a volcano on an island close to the Philippine capital have heeded official warning to evacuate as fears of an eruption grew, officials said on Monday.

The Philippine Institute of Volcanology and Seismology increased the alert level for Taal Volcano in Talisay town in Batangas, approximately 66 km south of Manila, on Sunday to 4 on a scale of 5, indicating an increased prospect of a hazardous eruption "within hours to days."

Level 4 means a hazardous eruption is in progress. The volcanic institute declared a permanent danger zone within Taal volcano's 14-km radius as the volcano spewed lava and ashes.

Volcano institute head Renato Solidum said the restive volcano spewed fountains of red-hot lava and massive ash flumes before dawn on Monday.

He said the institute has recorded a total of 52 volcanic earthquakes in the Taal region as of 12:49 a.m. on Monday.

"Such intense seismic activity probably signifies continuous magma intrusion beneath the Taal edifice, which may lead to further eruptive activity," Solidum said.

Mayor Gerry Natanuan of Talisay town in Batangas province said 45,000 people living near Taal volcano, a popular tourist spot, were evacuated Sunday night. He said that a few villagers who stayed to watch over their homes will eventually be forced to evacuate.

Batangas province Vice Governor Mark Leviste said there are 12 towns around the volcano but the towns of Talisay, Agoncillo, and Laurel towns are high-risk areas. The towns and Taal Volcano island is home to farmers, fishermen and tourist guides.

Leviste said there was zero visibility in some areas because of the thick ashfall on Sunday night. Some roads are covered with up to two inches of mud, he added.

Local television footage showed villagers covered in volcanic ash evacuated to safer ground overnight. People living in high-risk towns near the volcano donned masks for safety.

The institute said explosion of fine, dense ash drifted in many areas in provinces south and north of Manila.

"Fine ashfall can cause irritation and breathing problems especially among the elderly and children and it is particularly dangerous to the health," the institute warned. In addition, it said that "areas of ashfall have also experienced sulfurous smell which can also cause irritation."

The institute urged the affected residents to wear facemasks or damp cloth or towel, warning of the effects of "heavy and prolonged ash fall."

"Motorists are advised to drive with extreme caution as ash can cause poor visibility and, when wet, can make roads slippery," the institute said.

Civil aviation authorities have also advised aircraft to avoid airspace around Taal Volcano "as airborne ash and ballistic fragments from the eruption column pose hazards to aircraft."

The Manila International Airport Authorities shut down the operation of the Ninoy Aquino International Airport on Sunday following the eruption, resulting in the cancellation of international and domestic flights. Thousands of passengers have been stranded as a result.

The eruption also forced the government to cancel classes in the provinces blanketed by volcanic ash, including Metro Manila.

Visits to the 2,500-hectare crater island, a major tourist draw, were banned as the institute declared the entire island a permanent danger zone and should not be settled.

Taal is one of the most unstable of the country's 24 known active volcanos with 34 recorded eruptions.