WASHINGTON – President Bush yesterday called Prime Minister al-Maliki of Iraq to congratulate him on the formation of a new government and said Iraq’s transformation would be a “devastating defeat” for terrorists.

“The formation of the unity government in Iraq begins a new chapter in our relationship with Iraq,” Mr. Bush said in remarks from the White House. “I assured them that the United States will continue to assist the Iraqis in the formation of a free country.”

Mr. Maliki won parliamentary approval for his new cross-party government yesterday after five months of negotiations. American military commanders have said the new government will help to quell sectarian violence in Iraq that, according to President Talabani, killed more than 1,000 Iraqis in Baghdad last month and many more throughout the country.

Mr. Bush said Iraq would serve as an example for other countries that want to be free and would become an important ally in the war against terror.

The Iraqi Parliament approved Mr. Maliki, his 35 cabinet members, and two deputies yesterday. The government was unable to agree on who should take over the defense and interior ministries. Mr. Maliki will temporarily run the interior ministry and Deputy Prime Minister Salam al-Zaubai the defense ministry.

Secretary of State Rice said the failure to name a defense or interior minister is a result of the government being diligent in assuring they have the right people for the position rather than a sign of divisions in the government.

“When you take this kind of time, it shows a kind of determination and maturity,” Ms. Rice said on Fox News. “With the very difficult things that they’re trying to do, they are making extraordinary progress politically.”

Some Iraqi lawmakers walked out of the parliamentary session to protest the failure to fill the defense and interior posts, according to a live broadcast by Dubai, United Arab Emirates-based Al-Arabiya television station.

Senator McCain, a Republican of Arizona, expressed concern Iraq was unable to fill those two “key positions.”

“We should not get too optimistic but we should not think that we are going to fail, because we cannot afford to fail,” Mr. McCain said on Fox News Sunday.

Violence continued in Iraq, as at least 20 people were killed today, many in an explosion in a Baghdad restaurant, Agence France-Presse reported. At least another 18 were injured in an explosion at a crowded diner.

As many as 42,180 civilians have been killed in the conflict as of yesterday, according to an online tally by a London-based group that opposes the war and compiles its casualty toll from media reports and official statements, Iraq Body Count.

Ms. Rice said that, while the sectarian violence “is clearly now a major problem for Iraq,” the country’s new leadership understands that Iraqis are fed up with the continued violence.

Mr. Maliki has said “that he is determined to use maximum force to stop the terrorism and the violence against the Iraqi people,” Ms. Rice said. “This is a strong leader.”

As a permanently elected leader rather than an interim one, Mr. Maliki is demonstrating a “resolve” toward governing, Ms. Rice said. “We need to give him a little breathing space and a little chance here, and I think you’re going to see very good things from this government.”

The sectarian violence in Iraq was sparked by the February 22 bombing of the Golden Mosque in Samarra, which is sacred to the country’s majority Shiite Muslims. That was followed by attacks on Sunni mosques and other violence, prompting a former prime minister, Ayad Allawi, to say that Iraq had descended into civil war.

Support for the Iraq war has been dropping in America, with 62% of adults surveyed in a May 11-15 Washington Post-ABC News poll saying the conflict was not worth fighting. That dissatisfaction has pushed Mr. Bush’s approval ratings in the Post-ABC poll to 33%, a low point for his presidency.

America has about 130,000 troops in Iraq, as part of a coalition that numbers about 150,000. Mr. Bush has ruled out setting a timetable for their withdrawal, saying that plays into the hands of insurgents. Today Ms. Rice said it is premature to discuss any troop withdrawals at this stage, especially before consulting with the new Iraqi government. More than 2,400 American servicemen have died in Iraq since the March 2003 invasion.