Five climbers killed as Mayon volcano in Philippines erupts

One of the Philippines' most active volcanoes rumbled to life today, spewing room-sized rocks toward nearly 30 climbers, killing five and injuring others who had to be rescued with helicopters and rope.

The climbers and their Filipino guides had spent the night camping in two groups before setting out at daybreak for the crater of Mayon volcano when the sudden explosion of rocks, ash and plumes of smokes rocked the mountain, guide Kenneth Jesalva told the ABS-CBN TV network.

He said rocks "as big as a living room" came raining down, killing and injuring members of his group, some of whom were in critical condition. Jesalva said he rushed back to the base camp at 914 metres (3,000 ft) to call for help.

Among the dead were three Germans and their Filipino guide, said provincial governor Joey Salceda. He said everyone on the mountain had been accounted for at midday (local time), except for a foreigner who was presumed dead.

Eight people were injured, and Salceda said the others were in the process of being brought down the mountain. Ash clouds have cleared over the volcano, which was quiet later in the morning.

"The injured are all foreigners ... They cannot walk. If you can imagine, the boulders there are as big as cars. Some of them slid and rolled down. We will rappel the rescue team, and we will rappel them up again," he said from Legazpi, the provincial capital at the foothill of the mountain.

An Austrian mountaineer and two Spaniards escaped with bruising, he said.

Renato Solidum, the head of the Philippine Institute of Volcanology and Seismology said the eruption was not unusual for the 8,070-ft mountain which has blown about 40 times in the past 400 years.

In 2010, thousands of residents moved to temporary shelters when the volcano ejected ash up to five miles from the crater.

Solidum said no alert was raised after the latest eruption and no evacuation was being planned.

Climbers are not allowed when there is an alert, and the recent calm may have encouraged this week's trek.

However, Solidum said that even with no alert raised, the immediate zone around the volcano is supposed to be a no-go area because of the risk of a sudden eruption.