An Aug. 19 article incorrectly said that the Palestinian uprising was approaching its fifth anniversary. The uprising began in September 2000 and is nearing its fourth anniversary. (Published 8/25/04)

Israeli Prime Minister Ariel Sharon and Palestinian leader Yasser Arafat both confronted challenges from within their ranks Wednesday in speeches that aimed to quash growing internal rebellions over their leadership and policies.

Sharon made an impassioned plea for unity at a convention of his Likud Party in Tel Aviv Wednesday night, but members of the party's Central Committee rejected two measures intended to broaden support within his governing coalition for withdrawing Jewish settlers and Israeli troops from the Gaza Strip.

Likud members voted 843 to 612 against bringing the centrist Labor Party into the government, and they turned down Sharon's request to expand his coalition by negotiating "with any Zionist party" by just 12 votes, 765 to 753, Likud Party spokesman Shmuel Dahan said.

It was the second rebuke to Sharon by his party in four months. In May, Likud members overwhelmingly rejected his disengagement plan for Gaza in a nonbinding referendum. In his speech on Wednesday, Sharon once again said he would not bow to his party's wishes, declaring, "The Likud will conduct negotiations with all Zionist parties for expanding the coalition."

Warning that his party was headed toward "the verge of division and disintegration," Sharon told an alternately jeering and cheering crowd: "We have to decide whether the Likud will continue to lead the state united with responsibility, or the Likud will be led by an extreme, irresponsible, rebellious opposition."

Earlier, in an address to the Palestinian parliament at his compound in Ramallah, Arafat acknowledged corruption within the Palestinian Authority and, in a rare concession, said he was among those who had made mistakes, although he offered no concrete proposals for change.

"Some people in some institutions have misused their positions and were unfaithful in their jobs," Arafat said during a nearly 90-minute speech to the Palestinian Legislative Council, which frequently has complained about his unbridled power and failure to implement reforms.

"This includes everyone," he said, adding, "Everyone has made his own mistakes."

Yossi Alpher, co-founder of Bitterlemons.org, a Palestinian-Israeli Internet dialogue site, said Sharon's Gaza disengagement plan was the catalyst for political unrest on both sides. The proposal has not only triggered the right-wing revolt in Likud, but also has sparked bitter power struggles among Palestinians over who would eventually rule the impoverished and besieged coastal strip.

"For the last 20 years, whenever an Israeli government became destabilized, it was because of the Palestinian issue and the government's behavior towards the Palestinians, and now it's the same set of dynamics that's destabilizing Arafat's rule as well," Alpher said.

While Arafat could probably afford to ignore the challenges, Alpher said, Sharon will do so at his peril, because the opponents of his disengagement plan -- especially inhabitants of Jewish settlements in Gaza and the West Bank -- are highly motivated, well-funded and "the most energetic group on the political scene." They could bring down his government, he said.

The speeches and internecine strife came as the Palestinian intifada, or uprising, approaches its fifth anniversary. More than 2,700 Palestinians and about 980 Israelis have been killed in the conflict, and serious peace efforts collapsed more than a year ago.

Arafat has been the target of unprecedented criticism from within his Fatah political movement, as younger leaders demand a greater share of political power, far-ranging reforms and a crackdown on corruption. The al-Aqsa Martyrs Brigades, an armed faction of Fatah, recently called on Arafat to relinquish some of his powers and demanded that corrupt officials be fired and prosecuted.

Palestinian Prime Minister Ahmed Qureia resigned in July, complaining of "a level of chaos that we've never seen before," then withdrew his resignation when Arafat agreed to give him control over the Palestinian police and to consolidate about 12 security forces into three branches.

During his speech, Arafat said the Palestinian Authority "should open doors wide to the younger generation." He said a top priority should be reorganizing the security apparatus and "putting an end to the state of security chaos," but he made no proposals.

Even as Arafat conceded that some Palestinian officials had abused power and that he was among those who had made mistakes in not strengthening government institutions, independent lawmaker and former cabinet member Abdul Jawad Salah shouted, "You are the one who protected them!"

A flustered Arafat jabbed his finger toward Salah and shot back: "Be careful! Be careful!"

"He's not part of the reform, he's part of the corruption," Salah said after the speech, which was delivered in a refurbished meeting hall across from Arafat's battered offices.

Sharon's internal battles began in earnest in May, with the referendum defeat of his Gaza disengagement plan. His continued pursuit of the plan has divided the party, and he had to fire two ministers from the ultranationalist National Union party to get the plan through his own cabinet. Two ministers from the hard-right National Religious Party also quit, leaving Sharon's coalition with just 59 votes in the 120-seat parliament.

His government has been subjected to almost weekly no-confidence votes, spurring Sharon to reach out to Labor and other parties to broaden his coalition.

Before the balloting Wednesday night, many Likud members at the convention who said they were voting against Sharon explained that they simply could not stomach an alliance with Shimon Peres, the Labor Party chairman and architect of the 1993 Oslo peace accords.

"Peres will have an appeasement policy vis-a-vis Arafat and continue with the Oslo accords that are long dead," said Yitzhak Ben Gad, 60, a real estate agent and former deputy mayor of the coastal town of Netanya. "He thinks in terms of a new Middle East, but the Middle East we live in is old, and nothing has changed."

Special correspondent Samuel Sockol in Tel Aviv contributed to this report.

Palestinian leader Yasser Arafat responds to a heckler following his speech to a session of the Palestinian Legislative Council at his headquarters.Israeli Prime Minister Ariel Sharon speaks at a convention of his Likud Party, whose members rejected his attempts to broaden the governing coalition.