MANILA, Philippines -- The Philippines' most active volcano spewed fountains of lava and massive ash plumes overnight and Tuesday morning after authorities warned a violent eruption may be imminent.

Lava fountains reached up to 700 metres (2,300 feet) above Mount Mayon's crater and ash plumes rose up to 3 kilometres (1.9 miles) during the night and before daybreak, according to the Philippine Institute of Volcanology and Seismology. An explosive eruption Monday was the most powerful since the volcano started acting up more than a week ago.

Disaster officials in Albay province, where Mayon lies, say more than 30,000 people are staying in evacuation centres.

Officials raised Mayon's alert level to four on a scale of five, meaning a violent eruption is possible within hours or days. The danger zone expanded to 8 kilometres (5 miles) from the crater, affecting thousands more residents.

The eruptions have shrouded nearby villages in darkness and sent lava, rocks and debris cascading down Mayon's slopes toward the no-entry danger zone. There have no reports of deaths and injuries. Airplanes have been ordered to stay away from the crater and ash-laden winds and several flights have been cancelled.

Volcanic ash fell in about a dozen towns in coconut-growing Albay province and nearby Camarines Sur province, with visibility being heavily obscured in a few towns because of the thick grey ash fall, Jukes Nunez, an Albay provincial disaster response officer, said by telephone.

"It was like night time at noon, there was zero visibility in some areas because the ash fall was so thick," Nunez said.

More than 30,000 ash masks and about 5,000 sacks of rice, along with medicine, water and other supplies, were being sent to evacuation centres, Office of Civil Defence regional director Claudio Yucot said.

Mayon lies about 340 kilometres (210 miles) southeast of Manila. With its near-perfect cone, it is popular with climbers and tourists but has erupted about 50 times in the last 500 years, sometimes violently.

In 2013, an ash eruption killed five climbers who had ventured near the summit despite warnings. Its most destructive eruption, in 1814, killed more than 1,200 people and buried the town of Cagsawa in volcanic mud. The belfry of Cagsawa's stone church still juts from the ground in an eerie reminder of Mayon's fury.

The Philippines lies in the "Ring of Fire," a line of seismic faults surrounding the Pacific Ocean where earthquakes and volcanic activity are common.

In 1991, Mount Pinatubo in the northern Philippines exploded in one of the biggest volcanic eruptions of the 20th century, killing about 800 people.