Indonesian President Susilo Bambang Yudhoyono on Tuesday on behalf of the Indonesian people extended his heartfelt condolence to the accident of Malaysian airline plane MH370 that crashed into southern Indian Ocean and killed all 239 people on board.

President Yudhoyono made the statement on his twitter account following the announcement by Malaysian Prime Minister Najib Razak on Monday night that the plane losing contact on March 8 crashed into the ocean with none of passengers and crew alive. "Indonesia is mourning on the tragedy of MH370 plane,"President Yudhoyono said on his twitter account. "To the people of Malaysia and Prime Minister Najib Razak, we extend heartfelt condolence to this tragedy,"said Yudhoyono. "My deep condolences are to their families, and my prayer to those on MH370. May the soul of their loved ones rest in peace,"he said.

More than 150 out of 239 people on board are Chinese citizens and seven are Indonesian people.

Chinese and Australian rescue planes had seen debris, allegedly parts of MH370 plane, in a remote area in southern Indian Ocean, about 2,500 km southwest of Perth, Australia.

U.S. Navy has dispatched a device to find out the back box of the plane in the Indian Ocean.

The Indonesian government has deployed navy ships and planes to assist the rescue operation and is ready to ramp up assistance, Bambang Ervan, spokesman of Transport Ministry, told Xinhua.