JAKARTA, Nov. 5 (Xinhua) -- Rumbling Mount. Kelud in densely populated areas of East Java province have spewed dangerous clouds of white smoke, containing CO2 gas and other poisoning gas, senior official of monitoring posts of Mount. Kelud Umar Rosadi said on Monday.

    The shot of the hot smoke reached up to 800 meters into the sky, while tremors whose intensity had decreased began to rise on Monday, said the official.

    Rosadi said it could be dangerous if wind blows and carries smoke to the residential areas.

    "If the smoke is breathed in, it could be dangerous, because it contains CO2 gas and other gasses," he told Xinhua over telephone from the monitoring post near the mountain.

    Although most of the residents in dangerous zone on the slope of the mountain had already been evacuated, the official said that the wind may blow the smoke far away.

    All thousands of residents in the six-kilometer dangerous zone had been evacuated since the volcano has been on the top alert status last month.

    Rosadi, who is also a head of emergency management of Mount, Kelud activity, predicted that the crater temperature could soar.

    "The instrument recording the temperature was broken on Sunday due to high pressure. The latest temperature recorded was 77.2 degree Celsius," he said.

    He said that the authorities predicted three possibilities could happen in the next time, including the worse is a huge explosion that spew a large amount of materials from inside the mountain, or an explosion that only exited material at the surface of the volcano or the abortion of possible explosion.

    "Should the supply of energy from inside of the volcano persistently accumulated and the exiting of the energy from the crater could not make a balance, a huge explosion spewing all materials could occur, he said.

    But, Rosadi said that if the spewing of smoke could prevent the accumulation of energy, and it could be balanced, the volcano will not erupt.

    Over 10,000 people were killed when the mountain exploded in 1586.

    The mountain also erupted in 1901, 1919, 1951, 1966 and 1990.

    Mount. Kelud is part of the country's 129 active volcanoes, of which 66 of them are located in high-density population areas, Java and Sumatra islands, according to the country's meteorology agency.

    Indonesia is laid at a vulnerable zone so called "the Pacific Ring of Fire"" where two continental plates meet, causing frequent volcanic movements.