Millions of people live in the vicinity of the volcano, which has already killed more than 100 people [AFP

At least 64 people have been killed in the last 24 hours after clouds of blistering gas erupted from Indonesia's Mount Merapi volcano, prompting the country's president to call the eruptions a "national disaster".

Susilo Bambang Yudhoyono promised on Friday that his government would take "extraordinary measures" to respond to the ongoing crisis.

Many villagers suffered severe burns from the searing hot dust and debris that spewed out of the country’s most volatile volcano. The deadly clouds raced down the mountainside at more than 100km an hour, forcing villagers to flee.

Volcanologists said Friday's gas eruption was not only the largest since the the volcano first erupted on October 26, but the worst in a century.

Al Jazeera's Step Vaessen, reporting from the capital, Jakarta, said the gas eruption was still under way.

"It has not stopped erupting for the last 40 hours. Last night there was a huge eruption," she said.

"Villages were on fire, houses burned. Lots of people had to flee. Many wounded and many dead, but there are still people living on the slopes of Merapi."

Worse may be yet to come

More than 100 people in total have been killed by the eruptions.

Millions of people live in the vicinity of the volcano, in what is one of the most densely populated regions in Indonesia.

The increasingly violent activity defied initial predictions from volcanologists that the first eruption on October 26 would ease pressure inside the mountain.

To the contrary, the eruptions have only continued to amplify. And the gas pressure inside the mountain is increasing; leading experts to fear a much bigger eruption might be next.

The volcano first erupted on October 26 [AFP]

"It is very hard to predict in the first place what the Merapi is doing as well, it is the most unpredictable volcano in Indonesia. But this pattern that we've seen now in recent weeks is totally different from what we've seen ever in the past," our correspondent said.

While Yudhoyono said 2,000 soldiers would be sent to the area to help relieve efforts, he made no announcement of any plans to evacuate the area, our correspondent reported.

"Many people have been evacuated … But still people have to go back and forth to their villages, because their animals are there.

"So people are pleading to the government to help them so that not just the people are evacuated but the animals as well, so that they don’t have to go back to their villages all the time," she said.

The president said on Friday that the government would buy villagers' cattle in a bid to prevent them from returning and putting their lives at risk.

'Danger zone' extended

More than 75,000 people have been moved from the danger zone around the volcano.

That area was widened from 10 to 15km from the peak on Thursday after an eruption gave concern for a heightened threat. It has now been extended to 20km, but experts say it may need to be widened even further. The president made no comment on this in his appearance on Friday.

Merapi last erupted in 2006, when it sent an avalanche of pyroclastic ash - hot gases and rock fragments - racing down the mountain and killing two people.

A similar eruption in 1994 killed 60 people, while 1,300 people died in an eruption in 1930.

There are more than 129 active volcanoes in Indonesia, which are spread across 17,500 islands.

The country is prone to eruptions and earthquakes due to its location within the so-called Ring of Fire - a series of fault lines stretching from the western Hemisphere through Japan and Southeast Asia.

Source: Al Jazeera and agencies