BEIJING — Hong Kong's beleaguered chief executive, Tung Chee-hwa, announced yesterday that he was quitting his post because of health reasons, ending more than a week of official silence and unofficial speculation.

Despite the widely held view that his departure was the will of a Beijing government that has lost faith in him, Tung insisted that he was not fired.

"That is not the case at all," Tung said.

Tung's most likely successor is his second in command, Chief Secretary Donald Tsang. The bow-tie-wearing career civil servant, who won knighthood for his service under British rule, is a skilled administrator and a more popular politician than Tung.

Hong Kong Chief Secretary Donald Tsang

"He will understand the operations of government a lot better than Mr. Tung," said Christine Loh, head of Civic Exchange, an independent think tank in Hong Kong.

Tung's announcement marks the end of a tenure that began when he was chosen by Beijing to lead the former British colony upon its 1997 return to Chinese rule. The 67-year-old former shipping tycoon and political novice has dealt over some of the biggest problems in the island's recent history. From his handling of the Asian financial crisis to the outbreak of SARS, and a controversial anti-subversion bill, Tung has repeatedly fallen short of public expectations.

"They put in charge a man who didn't understand Hong Kong, had no clue about modern management or international politics," said Michael DeGolyer, director of the Hong Kong Transition Project at Hong Kong Baptist University. "He was basically clueless."

Half a million residents took to the streets in July 2003 demanding more political autonomy and Tung's resignation. Some observers describe it as a turning point.

"After the mass protest, Beijing thought Hong Kong was getting politically out of control," said Anthony Cheung, professor of public administration at the City University of Hong Kong. In December Chinese President Hu Jintao openly criticized Hong Kong leaders' poor performance, signaling the beginning of the end for Tung.

Some see Tung as a victim of the "one country two systems" political framework that Beijing installed for Hong Kong. His job has been to serve two masters with often conflicting demands: the people of Hong Kong and the Communist Party in Beijing.

Tung also may be a casualty of factional infighting in Beijing. Tung was basically hired by former Chinese President Jiang Zemin, who relinquished his last official post during the current session of the annual National People's Congress. With Hu fully in charge, he may have wanted to clean house.