JAKARTA, Dec. 30 (Xinhua) -- Indonesian authorities have prohibited tourists from hiking in the radius of 4 km from the crater of Mount Agung volcano, which erupted on Sunday, while residents in the slope of the mountain have been ordered to exercise caution over the flow of lava during heavy downpours, disaster agency official said.

The eruption of Mount Agung triggered rain of volcanic ash covering eight villages and town in Karang Asem district, but did not lead to evacuation, Ida Bagus Ketut Arimbawa, head of the operational department of the disaster management and mitigation agency in the district told Xinhua over the phone.

But the height of column of the volcanic ash spewed could not be found out as the volcano was covered by heavy clouds, the official said.

"Tourists and residents are not allowed to hike the mountain, the activity is only allowed to be undertaken in the area of beyond five kilometers from the crater," said Ketut.

The beautiful Bali tourist resort is the center of the Indonesian tourism industry, nearly 600,000 out of over one million foreign tourists coming into Indonesia every month would spend their time on Bali island, according to data from the national statistics bureau.

As rain has started pouring down on Bali since November, the start of Wet season in Indonesia, Ketut said that officials of the agency had called the people living along Tukadiasyah river whose upstream is in the flank of Mount Agung volcano to keep alert on possible floods carrying huge amount of cold lava and other volcanic materials during heavy downpours.

"For now, lava and several volcanic materials have already flown into the upstream of the river. Rain has poured down frequently, but the heavy downpours, which will swept lava and volcanic materials to downstream, have not occurred by far," said Ketut.

Mount Agung, situated about 70 km from the tourist hub of Kuta, has weathered a series of eruption since September 2017, shooting a column of volcanic ash into the sky with chucks of lava tumbling down its slope, according to the country's volcanology agency.

The eruption has harmed aviation and forced over 144,000 people to flee home, the disaster agency said.

In its last eruption in 1963, more than 1,100 people were killed.

Mount Agung volcano is one of the 129 active volcanoes in Indonesia, a vast archipelagic nation home to over 17,500 islands.