Updated

Australia (search) said Monday it would press on with its humanitarian mission on earthquake-hit Nias Island (search) despite the loss of a navy helicopter in a crash that killed nine people.

Also Monday, thousands of students in Gunung Sitoli (search), the capital of Nias, turned up at schools only to find that classes could not be held because most school buildings were damaged from the powerful earthquake that hit a week ago and many teachers had not turned up.

At the Santo Xaverius school, around 100 students sat on the basketball court looking at the remains of the three-story school whose top floor had caved in.

"I heard that school will start today but I am disappointed because I have been told there will be no studies," said Kurnia Faahakhododo, 19, a senior high student.

The 30-year-old Australian Sea King navy helicopter hit the ground nose first and burst into flames on Saturday while flying from its base, hospital ship HMAS Kanimbla, to a remote village in Nias.

"They gave their lives trying to help other people. The mission will continue. It is important we honor their memory," Cmdr. George McGuire, the commander of the Australian relief mission on Nias, said Monday.

The Australian navy, however, grounded its remaining fleet of aging Sea King helicopters Monday pending an investigation into the tragedy.

"We've decided that for the moment, until we find out more detail about exactly what occurred and why, that we won't fly," Rear Admiral Rowan Moffitt told reporters in Sydney.

The bodies of the victims — six navy and three air force personnel — were being sent back to Australia, McGuire, who is also the captain of Kanimbla, told The Associated Press.

Indonesian President Susilo Bambang Yudhoyono, in Australia on his first visit as his nation's leader, announced the dead and the two survivors will be awarded medals of honor.

The 8.7 magnitude quake that hit last Monday came as the region was still recovering from the Dec. 26 earthquake and tsunami that killed at least 126,000 people in Indonesia, mostly in the nearby province of Aceh.

Last week's quake hit Nias and a string of other islands off Sumatra. At least 647 people including 616 on Nias have been confirmed killed, national police spokesman Col. Zainuri Lubis said Monday, raising the death toll by about 100 people.

He said the damaged or collapsed buildings in Nias, a predominantly Christian island, include 6,736 houses, 123 shops, 16 mosques, 105 churches and 147 schools.

The area also continues to be hit by aftershocks. U.S. seismologists said two temblors of magnitudes 6.1 and 6.3 were recorded Sunday, sending worshippers mourning the late John Paul II at a Mass on Nias rushing outside the cathedral. No damage or injuries were reported.