Agam (Indonesia) -- Hundreds of Indonesian rescuers were racing Tuesday to find a dozen hikers who went missing after a volcano eruption killed 11 people.

The dead hikers were found Monday near the crater of Mount Marapi on the island of Sumatra, while others were found alive and carried down the mountain in arduous rescue efforts hampered by further eruptions and bad weather.

The volcano spewed an ash tower 3,000 meters (9,800 feet) -- taller than the volcano itself -- into the sky on Sunday.

"This morning we will deploy around 200 personnel, on top of the personnel who are already staying up there. Until now five bodies have been brought down," Hendri, head of operations at the Padang Search and Rescue Agency, told AFP Tuesday.

"The volcano is still erupting," said the official, who like many Indonesians goes by one name.

He said the 12 hikers remained missing as of Tuesday morning and six dead bodies were still to be evacuated, with five brought down the mountain for identification.

The rescuers would attempt manual evacuations when possible, walking to the top of the volcano and evacuating the victims using stretchers because of ongoing eruptions and poor visibility, Hendri said.

Ahmad Rifandi, head of Marapi's monitoring post, told AFP Tuesday it had observed five eruptions from midnight to 8:00 am local time (0100 GMT).

"Marapi is still very much active. We can't see the height of the column because it's covered by the cloud," he said.

Abdul Malik, head of Padang Search and Rescue Agency told reporters Monday that three hikers found alive on the mountain after the eruption were injured but taken to hospital for medical treatment.

The head of Indonesia's volcanology agency, Hendra Gunawan, said Marapi has been at the second level of a four-tier alert system since 2011, and a three-kilometer exclusion zone had been imposed around its crater.

He appeared to blame hikers on Monday for going too close to the crater, saying the agency recommended no human activities in that zone, and emphasized that "severe impacts" were reported for victims within one to 1.5 kilometers from the crater.

Still hope

Officials said the hikers had registered through an online booking system, but others may have been on illegal mountain routes.

Relatives were still waiting for updates at an information center at the base of the mountain.

"I will stay here until I hear some news," said Dasman, father of missing hiker Zakir Habibi, who made a two-hour drive from Padang city to the base of the mountain last night in hope of good news.

"I still hope my son survives," he said on Monday.

A total of 75 hikers were listed by officials as hiking on the mountain since Saturday, with 49 initially accounted for and some suffering burns and fractures.

The search will carry on for seven days, rescue officials said.

Those killed were severely burned and forensic workers were preparing to identify the dead by dental and fingerprint records, or based on marks on their bodies, said Eka Purnamasari, an official from the West Sumatra police medical unit.

Mount Marapi, which means 'Mountain of Fire', is the most active volcano on Sumatra island.

Indonesia experiences frequent seismic and volcanic activity due to its position on the Pacific "Ring of Fire", where tectonic plates collide.

The archipelago nation has nearly 130 active volcanoes.