Five more bodies were discovered near the peak of Mount Ontake in central Japan on Monday, bringing the number of those confirmed or feared dead after Saturday’s volcanic eruption to 36, authorities said.

But the effort to recover bodies from the volcano’s ash-coated slopes has been hampered as the 10,000-foot-high mountain, about 125 miles west of Tokyo, continues to erupt.

Plumes of gray smoke were seen billowing from the volcano Monday, with ash and toxic gas forcing rescuers to suspend their efforts to bring down bodies from the peak. Japan’s Meteorological Agency warned that the mountain could erupt again in the next few days.

But before the suspension, eight bodies were lifted off the mountain Monday morning, bringing the total number of victims recovered to 12; four were brought down Sunday. With the discovery of five more bodies atop the mountain, authorities said at least 36 people are thought to have been killed when the volcano erupted without warning shortly before lunchtime Saturday.

Many of the bodies were found on a trail connecting a shrine near the peak and a lodge about 550 yards below, police said, according to Japan’s Kyodo news agency, while others had been buried in ash as much as 20 inches deep.

About 550 police officers, firefighters and military personnel are involved in the rescue effort, and Japanese media showed scenes of soldiers carrying body bags to a military helicopter that had landed on the ash.

The bodies were being examined at an elementary school in the nearby town of Kiso, while the families of the missing waited at a nearby municipal hall, the Associated Press reported.

Japan is no stranger to seismic activity, but this is the first time in more than two decades that anyone has died as a result of a volcanic explosion. Mount Unzen on the southwestern island of Kyushu erupted in 1991, killing 43 people.

The Meteorological Agency, responsible for monitoring volcanic activity, has come under intense scrutiny here for not giving any warning of the eruption. The mountain, a popular hiking destination because of its well-marked trails and numerous lodges, was crowded with hikers enjoying the start of the autumn foliage viewing season when the eruption occurred.

The agency has raised the warning level to 3, advising people to not go near the volcano. Level 5 is an order to evacuate.

Mount Ontake’s eruption was deemed a “phreatic explosion,” when magma in the volcano rapidly heats water, creating steam and causing an eruption.

The agency might have to reconsider its surveillance system, said Yoshihide Suga, the chief cabinet secretary. “However, I believe that, given current levels of knowledge, they made the only judgment they could,” he told reporters Monday, according to the Reuters news agency.