Secretary of State Condoleezza Rice made an unannounced trip to Iraq on Friday, where she encouraged the country's Sunni Arab minority to participate next month in elections envisioned as the final phase of Iraq's U.S.-designed political transition.

"If Iraq does not succeed, and should Iraq become a place of despair, generations of Americans would also be condemned to fear," Rice said in the northern city of Mosul, her first stop. "So our fates and our futures are very much linked."

Rice's visit to heavily fortified and U.S.-controlled areas of Mosul and Baghdad, which for security reasons was not publicized in either city until after she landed, reflects the Bush administration's deepening concern that Sunni political alienation will undermine the elections -- and the prospects of establishing sufficient security for the United States to begin withdrawing troops next year.

In Baghdad, Rice stressed that differences of "history or tradition, culture or ethnicity" could be strengths rather than weaknesses in a democratic political process. At a joint press conference with Prime Minister Ibrahim Jafari, she said that a country emerging from decades of tyranny and months of political violence had to "find a balance between inclusion and reconciliation and justice."

The challenge of repairing Sunni-Shiite relations was underscored Thursday by a suicide bombing at a popular Baghdad restaurant that killed 35 people, many of whom were members of the capital's Shiite-dominated security services. The insurgent group al Qaeda in Iraq asserted responsibility for the blast, saying in a statement posted on the Internet that it had targeted Shiites in retaliation for the killings of Sunnis in a U.S. and Iraqi military offensive in western Iraq.

"Who created the sectarian attitude in Iraq? The occupation," said Salih Mutlaq, a Sunni politician who did not attend any meetings with Rice. "We never heard of this before in our history. But it's good that Condoleezza Rice realizes sectarianism is not good for Iraq. All we want from them is fair and clean elections next month."

Another Sunni leader, Hussein Shukur Falluji, said Rice's visit was aimed more at shoring up flagging political support in the United States than forging consensus here. "This is all for the benefit of the American administration, to save their army from the Iraqi resistance strikes," he said.

In another reflection of sectarian tensions, Jafari was almost dismissive of a new Arab League effort to organize a national reconciliation conference before the Dec. 15 elections. The prime minister, a member of Iraq's Shiite Muslim majority, rejected any prospect that participants could include either insurgents or former high-level members of Saddam Hussein's outlawed Baath Party. Both groups are largely Sunni.

Only those who have been involved in the political process, whether in the National Assembly or writing the new constitution, should be included in such a conference, Jafari told reporters. He said Iraq would continue its own efforts toward reconciliation after the elections.

The proposal by the Arab League -- a body representing 22 Arab countries, most of them Sunni-dominated -- is the only major regional effort to broker a compromise and prevent the Iraqi insurgency from causing a civil war. Several Arab countries, particularly in the Persian Gulf, have expressed concern that Iraq's current, Shiite-led government threatens the balance of sectarian power -- especially with Shiite-dominated Iran next door.

Rice said the United States supported regional efforts to bridge differences among Iraqis, but she, too, was cautious about who should be eligible to participate. All parties who attend should recognize that they are participating with an elected Iraqi government, she said, adding, "The lead on this really ought to be the Iraqi government."

Rice's visit took place against a backdrop of continuing violence.

The U.S. military announced Friday that two soldiers died Thursday of wounds caused by small-arms fire during fighting near Habbaniyah, about 50 miles west of Baghdad. And a Marine was killed Thursday by a roadside bomb in Karabilah, near the border with Syria, where U.S. and Iraqi troops are engaged in a major offensive to clear the area of insurgent safe houses and smuggling networks.

In Baghdad on Thursday, U.S. forces stormed a house sheltering a cell of suicide bombers, killing seven suspected terrorists, including one wearing an explosive vest, and capturing five, the military reported in a statement Friday.

In Baqubah, about 35 miles northeast of Baghdad, three policemen were killed and two wounded when seven gunmen opened fire on a checkpoint, a police spokesman said.

Meanwhile, an Arabic-language Web site posted an announcement Friday that former Iraqi vice president Izzat Ibrahim Douri, a key confidant of Saddam Hussein's, had died earlier in the day. The report could not be independently confirmed, and the British-based Web site did not report the place or cause of Douri's death.

Douri, who would be about 63, reportedly suffered from leukemia. He is considered the highest-ranking member of Hussein's inner circle still at large -- the "king of clubs" in the U.S. card deck of wanted Iraqis -- and is believed to be an important strategist in the Iraqi insurgency.

Correspondent Jackie Spinner and special correspondents K.I. Ibrahim and Bassam Sebti contributed to this report.

Secretary of State Condoleezza Rice joins Iraqi Prime Minister Ibrahim Jafari, right, at Baghdad news conference.