TOKYO, Sept. 29 (Xinhua) -- Rescue operations for survivors and victims were halted Tuesday on Mountain Ontake in central Japan after Saturday's deadly eruption as volcanic activities are intensified, according to local media.

"Volcanic tremors have become bigger since early morning and their intensity is almost the same as observed on Saturday night," an official at the Japan Meteorological Agency was quoted as saying.

Local authorities decided to suspend the rescue efforts which involve about 850 police, firefighters and members of Japan's Self- Defense Forces, said the Kyodo News.

A total of 12 people were declared dead on Monday, while 24 others whose bodies were still on the peak area were listed as suffering heart and lung failure. The death toll of the disaster is expected to rise.

Japanese police agency also said at least 69 others were injured in the eruption.

The 3,067-meter volcano erupted shortly before noon Saturday during a climbing season. Its last major eruption was in 1979 and had some minor volcanic activities in 1991 and 2007.