Toxic gases and ash from still-erupting Mount Ontake has forced Japanese rescue workers to call off the search for more victims as dozens of relatives awaited news of their family members.

Rescuers found five more bodies near the summit of the volcano, bringing the death toll to 36, but 24 of the bodies remain on the volcano, the Japanese newspaper Mainichi Shimbun reported on Tuesday.

Earlier, rescuers managed to airlift only 12 bodies off the mountain since the start of the eruption on Saturday because of dangerous conditions.

How the victims died remains unclear, though experts said it was probably from suffocating ash, falling rocks, toxic gases or some combination of them. Some of the bodies had severe contusions.

Survivors told Japanese media that they were pelted by rocks from the eruption.

One man said he fled with others to the basement of a lodge, fearing that the rocks would penetrate the roof.

Yuji Tsuno, a veteran mountain photographer, was near the summit. After taking pictures of the initial explosion as ash and debris rained down, he quickly took refuge in a nearby hut, he told the TBS TV network.

About 20 minutes later, when the smoke partially subsided, he rushed out and began his descent. It was a gamble, but he believed it was his only chance, he said.

"I almost thought it was the end of my life,'' he said in the interview.

On his way down, he spotted a man heading up. "I told him to go down with me, but he said he had to check on his child up there. I couldn't stop him," Tsuno said.

Surprise eruption

The eruption caught seismologists by surprise.

Although somewhat increased seismic activity had been recorded for about two weeks, there were no indications of a major eruption, said Satoshi Deguchi, a Japan Meteorological Agency official in Nagano prefecture.

Typical signs, such as increased seismic rattling or underground structural movement, were not detected.

Japanese TV showed soldiers carrying a series of body bags on Monday morning to a military helicopter that had landed in a relatively wide-open area of the now bleak landscape, its rotors still spinning.

The bodies were flown to a nearby athletic field and then taken to a small wooden elementary school in the nearby town of Kiso, where they were being examined in the gymnasium.

Family members of the missing waited at a nearby municipal hall.

More than 200 soldiers and firefighters, including units with gas detection equipment, were part of the search mission near the peak, said Katsunori Morimoto, an official in the village of Otaki.

The effort was halted because of an increase in toxic gas and ash as the volcano continued to spew fumes, he said, adding that the rescuers reported a strong smell of sulfur.

Al Jazeera's Wayne Hay, reporting near the near Mount Ontake, said that authorities have warned that it is possible that there could be another large eruption.

The eruption was the first fatal one in modern times at the 3,067-metre mountain, a popular climbing destination 210- kilometres west of Tokyo. An eruption occurred in 1979, but no one died.

The Mainichi Shimbun reported that Prime Minister Shinzo Ave has told parliament on Monday, that the government will "do its utmost efforts to rescue the climbers".