Leaders of China and the Philippines have expressed deep sorrow over the hostage crisis that ended in the deaths of eight tourists from China's Hong Kong, while a working team sent by the Chinese government has arrived in Manila to deal with the aftermath.

Chinese President Hu Jintao and Premier Wen Jiabao on Tuesday expressed their condolences to the families of the eight Hong Kong tourists killed during Monday's hostage crisis in the Philippines.

In a joint letter to Donald Tsang Yam-kuen, chief executive of Hong Kong Special Administrative Region (SAR), Hu and Wen expressed their deep sorrow for the families of those killed and consolation for the injured.

"We are in grave shock and grief on hearing that eight Hong Kong compatriots fell and many others were injured in the Manila hostage incident," the letter said.

"We hereby express our grave condolences and our deep sympathy to the families of the Hong Kong compatriots, and we hope the injured will recover soon," the letter said.

Chinese Vice President Xi Jinping on Tuesday also expressed his condolence in a letter to Tsang.

Philippine President Benigno Aquino III has declared Aug. 25 a day of national mourning for the victims of the hostage crisis.

Presidential Spokesman Edwin Lacierda said Tuesday that Aquino has ordered all government agencies, including the country's embassies and consulates abroad, to lower the Philippine flag at half-mast.

The eleven-hour hostage crisis in the Philippine capital Manila ended with the death of eight tourists from Hong Kong. Thirteen other Hong Kong tourists survived the ordeal, seven of them injured.

The hijacker, former Police Senior Inspector Rolando Mendoza, was killed after police raided the bus following failed negotiations to save the hostages.

The Chinese government has strongly condemned the hostage crisis and demanded the Philippine government thoroughly investigate the incident.

Foreign Minister Yang Jiechi, during a telephone conversation with his Philippine counterpart Alberto Romulo, said the Chinese government was shocked about the incident, deplored the slaying of the Hong Kong tourists, and strongly condemned brutality against innocent tourists.

The Chinese government demands the Philippine government launch a thorough investigation into the incident and inform the Chinese side of related details as soon as possible, he said.

Meanwhile, a working team sent by the Chinese government to deal with the hostage crisis arrived in Manila on Tuesday morning, accompanied by Chinese Ambassador to the Philippines Liu Jianchao, who had terminated his work report in Beijing ahead of schedule.