Zhang Ziyi and Bo Xilai Sex scandal Photos

BEIJING, May 25 (Reuters) - Chinese President Hu Jintao has demanded senior Communist Party officials stifle tensions over the ousting of ambitious politician Bo Xilai and show unity as they prepare for a change of leadership, sources briefed on recent meetings said.Zhang Ziyi and Bo Xilai Sex scandal Photos

Hu urged the party to close ranks at a meeting of about 200 officials early this month at a Beijing hotel, declaring the downfall of Bo - China's biggest political scandal in two decades - to be an "isolated case", the three sources said.

The sources' comments represent the first confirmation of speculation that Hu recently intervened to prevent a wider rift in the party and to resist pressure from some elements for a wider purge of the populist Bo's policies and supporters.

Bo, former party chief of Chongqing city, was suspended from the party's top ranks in April after his wife became a suspect in the murder of British businessman Neil Heywood. Before the scandal broke, Bo had been seen as a candidate to join China's new top leadership team to be unveiled this year.

"It's been settled that this will be dealt with as a criminal case, not a political case," said one of the sources, a retired official. "The central leadership wants to focus on ensuring a stable environment for the 18th Party Congress, so the guiding policy is to end all the rumours and contention."

The party congress, scheduled to be held late this year, will appoint a new generation of leaders. Hu and Premier Wen Jiabao will then step down from their government posts at the National People's Congress in early 2013, when Vice President Xi Jinping is likely to succeed Hu as president.

The sources, all with ties to senior party officials, spoke on condition of anonymity to avoid possible recriminations for speaking about internal party discussions.

Two of them said Hu had convened this month's meeting at the Jingxi Hotel, the party's heavily guarded conference hotel in western Beijing where leaders often hold secretive conclaves.

The meeting was part of a series of steps taken to shore up unity and advance preparations for the 18th Party Congress. Those steps included retired leaders, especially former president Jiang Zemin, giving their backing to Hu's position.

"Jiang said that if you have solid evidence that Gu Kailai committed murder and that Bo Xilai also committed major errors, then deal with it as an isolated criminal incident," said the retired official, paraphrasing a summary of Jiang's comments.

"There's already been too much instability. The overriding goal now must be a successful 18th Party Congress," the former official said, paraphrasing Jiang, 85, who a decade after he retired still exercises some influence over major decisions. One of the sources said Jiang was not at the Jingxi meeting and it was unclear where he made the remarks or how he conveyed them.