BEIJING — The Communist Party boss of China’s financial hub, Shanghai, was sacked yesterday in the most significant purge of the country’s secretive inner leadership for more than a decade.

Chen Liangyu, who sat on the 24-man ruling Politburo as well as running China’s largest city, was caught up in a corruption investigation over hundreds of millions of dollars siphoned out of its pension fund.

He was accused of “baneful” crimes, including business cronyism, covering up offenses by staff, and nepotism. It was rumored that he had been detained.

“Chen’s punishment fully demonstrates the central committee’s resolution to build a clean party and to fight corruption,” the state news agency said.

His fall exactly mirrors the sacking in 1995 of the person who was party boss of Beijing at the time and also a politburo member.

Although corruption was again the stated reason, it was widely believed the victim had lent his weight to a challenge to Jiang Zemin, who was trying to consolidate his leadership at the time.

Diplomats say the sacking was a “decisive” pre-emptive strike by the President Hu.

Mr. Hu is aiming to smother internal opposition to his plans to re-engineer the party leadership in his own dour image. Mr. Chen was a member of the socalled Shanghai gang of politicians close to the former president, Mr. Jiang.

A number of officials linked to the Shanghai gang have been removed for corruption and decadent living in recent months, with Mr. Chen merely the biggest fish so far.

Since Mr. Hu came to power in 2003, he has tried to moderate the pro-western, pro-business policies of Mr. Jiang in favor of ones that are more egalitarian and, some say, more repressive and anti-foreign.

Shanghai, with its gleaming new finance districts, Prada boutiques, and expensive restaurants, is the country’s greatest symbol of both “opening up” and corruption.

Mr. Chen made what was in retrospect a major tactical error two years ago by challenging Mr. Hu’s new approach.

Wen Wei Po newspaper, Beijing’s main mouthpiece in Hong Kong, said a major reshuffle of provincial leaders would occur over the next few months.

It said Beijing needed to reassert control over local opposition to its plans to rein in the economy, a move that could have worldwide repercussions.

Mr. Chen’s removal was seen as a key maneuver before a party congress — held every five years — due to be held in a year’s time, when a new Politburo will be named. The meeting will be Mr. Hu’s big opportunity to appoint a lieutenant who would in due course become his successor as leader.