At least one person has been killed and dozens suffered severe burns after the Mount Semeru volcano in Indonesia’s East Java province erupted on Saturday, forcing thousands to flee.

Videos shared on Saturday by the country’s disaster mitigation agency (BNPB) showed residents running in panic as towering smoke and ash blanketed some nearby villages in Lumajang district.

Two other people were reported missing and eight were trapped in debris, authorities said.

More than 300 families with children took shelter in badly hit Curah Kerobokan village in Lumajang after their houses were destroyed by volcanic ash and lava.

The deputy chief of Lumajang district, Indah Masdar, told a news conference one person had died and 41 people had suffered burn injuries.

"We brought the injured to health centres and for those whose burns are very serious were rushed to hospitals,” Masdar said.

Thick debris and knee-level cold lava floods made it difficult for rescuers to search for the two missing locals and to evacuate eight people trapped in a building covered by mud.

Masdar asked for helicopters to rescue people trapped inside buildings. "We’re in big distress. It’s harrowing, their families are all crying.”

Thoriqul Haq, district head of Lumajang, said a number of sand miners were trapped near mines.

Haq told Reuters that the road and bridge connecting Lumajang and the nearby city of Malang were severed.

"This has been a very pressing, rapid condition since it erupted,” he said. Haq added that evacuations were under way.

He later told news channel MetroTV that the severed bridge meant one nearby district had no access to medical help.

"Thick columns of ash have turned several villages to darkness,” Haq told TV One, adding that several hundred people were moved to temporary shelters or left for other safe areas.

Authorities were setting up evacuation tents, but evacuations have been hampered by thick smoke, BNPB chief Suharyanto said.

The national mitigation agency said it has dispatched a team to help people at shelters but thick debris from volcanic ash had prevented them from reaching the destination.

The Indonesian Meteorology and Geophysics Agency said its satellite images show volcanic ash has entered the Indian Ocean in the southern part of Java island.

Television reports showed people running in panic under a huge ash cloud, their faces wet from rain mixed with volcanic dust.

AirNav Indonesia, which controls Indonesian airspace, said in a statement the eruption did not "cause significant impact” on flights.

The 3,676-metre (12,060-foot) Semeru, the highest on the country’s most densely populated island, is among Indonesia’s nearly 130 active volcanoes. It erupted in January, causing no casualties.

Indonesia, an archipelago of more than 270 million people, is prone to earthquakes and volcanic activity because it sits along the Pacific "Ring of Fire,” a horseshoe-shaped series of fault lines. Indonesia has about 128 active volcanoes.