More than 76,000 people fled their homes, and flights were grounded across most of Indonesia's densely populated island of Java on Friday after a volcanic eruption sent a plume of ash and sand 17 km into the air.

The ash cloud from Thursday night's eruption of Mount Kelud in East Java province moved west over the island, forcing the closure of seven airports and stranding thousands of passengers. The only major airports still operating on the island were two in the capital, Jakarta.

"Based on verified data, over 76,000 people have been evacuated from five cities around the volcano ... and about 200,000 people were affected," National Disaster Mitigation Agency spokesman Sutopo Nugroho said in a text message.

Villagers in eastern Java described the terror of volcanic material raining down on their homes, while AFP correspondents saw residents covered in dust fleeing in cars and on motorbikes toward evacuation centers.

Mount Kelud is 90 km south of Indonesia's second-biggest city Surabaya, a major industrial center. Its airport was closed, along with those of Bandung, Yogyakarta, Solo, Malang, Semarang and the major oil refinery town of Cilacap.

They were expected to reopen on Saturday morning, a transport ministry official said.

Mount Kelud is one of 130 active volcanoes in the world's fourth-most populous country, and sits along the "Ring of Fire" volcanic belt around the shores of the Pacific Ocean.

Nugroho said the eruptions had ceased, but the ash had spread as far as 500 km to the west and northwest.

Television broadcast images of planes, streets and houses blanketed in a layer of gray ash.

At the world's largest Buddhist temple outside Yogyakarta, nearly 135 km away, workers rushed to cover statues with plastic sheets to protect them from the falling ash.

Other airports, including Denpasar on the resort island of Bali, were so far unaffected, according to flag carrier Garuda Indonesia.

Operations were also unaffected at a major oil refinery in Cilacap run by state-owned energy company Pertamina, officials said. The refinery, with a capacity of 348,000 barrels per day, accounts for a little more than a third of Indonesia's total output of refined products.

"Thankfully, Cilacap operations are normal, although ash has indeed reached the Cilacap area," said Pertamina spokesman Ali Mundakir. "As a preventive measure, we have immediately prepared air filters for equipment there."

East Java is the main area in Indonesia for sugar cane plantations, but officials expected limited damage to crops.

"The eruption will affect sugar cane plantations, but the impact is small," Soemitro Samadikoen, chairman of the Indonesian Sugarcane Farmers Association, said. "With this very small impact and high stock (in the domestic market), we do not need to import white sugar from other countries."

Nugroho said the disaster mitigation agency had confirmed that two people were killed after roofs collapsed under the weight of the fallen ash.