China yesterday mourned the 70 victims of the No 361 submarine disaster, but mystery continues to surround the cause of the accident. While coming to terms with the tragedy, some found a silver lining in the unusually forthcoming official admission of the accident. Jiang Zemin, chairman of the Central Military Commission, sent letters of condolence to families of the victims on Friday, and President Hu Jintao last night said publicly that the deaths were a huge loss to the People's Liberation Army navy. Front-page headlines of Mr Jiang sending his condolences to the seamen's families topped newspapers yesterday, along with the brief official Xinhua report attributing the cause of the accident to 'mechanical malfunction'. There was an outpouring of grief in Internet chat rooms as people paid their respects to the crew who sacrificed their lives for their country. Others demanded a thorough investigation of the disaster. In Taiwan, independent lawmaker Lin Chin-hsing claimed that Taiwan, the United States and Japan were aware of the accident before it had been officially announced. Mr Lin, who sits on the Legislative Yuan's defence committee, said he had been told by sources that the PLA planned to punish senior officers. For military buffs, the Ming-class submarine highlighted the backwardness of the Chinese navy. The diesel-powered craft of 1970s vintage is obsolete by today's standards of military hardware. Some commentators focused on the inadequacy of crew training and craft maintenance, which might have meant technical problems went undetected. 'It is a bitter lesson that our naval modernisation will be a long and arduous journey,' one chat room commentator noted. Others applauded the apparent openness of the government after the disaster. In the popular Sina.com chat room, one person wrote that the greater media transparency about the accident reflected a more confident central government leadership in the face of crisis. Yesterday, foreign leaders including German Chancellor Gerhard Schroeder, Japanese Prime Minister Junichiro Koizumi and Russian President Vladimir Putin sent condolence telegrams to President Hu and Mr Jiang. In the port city of Yantai, in Penglai county just off the Changdao islands where Xinhua said the submarine accident occurred, fishermen said they had only heard about the incident a few days ago. However, members of the small community could not agree on where the wreckage of the vessel had been taken. Some said the submarine had been towed to a small naval base on the Changdao islands, while others said it was now at a naval base in Weihai. Military analysts have rushed to offer their explanations of the cause of the accident. 'We are all guessing as the Xinhua report did not say much,' Ma Ding-shing, a Hong Kong-based military analyst, said yesterday. 'Such a high number of deaths usually stems from the boat splitting into two or exploding.' Russia's Interfax news agency quoted military sources as saying that the accident might have been caused by an onboard fire triggered by an electrical fault or torpedo explosion.