The U.S. hoped the installation Saturday of Iraq's new national unity government would help clear the way for the withdrawal of American troops.

"It is our wish that, as the government strengthens in its governing, Iraqis can protect themselves and American troops can come home," Republican House Speaker Dennis Hastert said in a statement.

In Baghdad, U.S. Ambassador Zalmay Khalilzad said the new government moves Iraq closer to providing for its own defense, but he avoided any specific date for a major withdrawal of American forces.

"Although there may be tactical increases here and there, strategically we're going to be moving in the direction of downsizing our forces," Khalilzad told reporters after the ceremony. He cautioned that changes in force levels are "always dependent on the conditions."

The move toward democracy in Iraq, which began with the U.S.-led invasion that toppled Saddam Hussein's regime, was slowed in recent months by political infighting as representatives debated the roles of various factions in the new government. Meanwhile, violence continued to wrack the capital and many other areas of the country.

In a speech in Chicago on Monday, President George W. Bush is to talk about how the new government represents an opportunity for Iraq to move forward because it has a four-year mandate, not just a temporary hold on power.

Hastert said the United States will continue to stand alongside the Iraqi people as they make political reforms and move past years of violent oppression under Hussein.

A Defense Department official said Friday that U.S. military commanders are sending several hundred additional American troops to Iraq to bolster security as the new government takes shape in Baghdad. The extra troops are from a 1st Armored Division battalion that has been stationed in Kuwait as a reserve force.

CountryWatch: Iraq

Bush has cautioned against withdrawing troops too soon.

"It's really important for us to understand that if we leave too early, the new democracy will falter," Bush said Friday at Northern Kentucky University. "It's in the nation's interest that democracy prevail because democracies help yield the peace."

U.S. officials waited to see whether Sunni leaders, including parliament speaker Mahmoud al-Mashhadani, would have influence over armed Sunni groups in rebel strongholds.

A senior administration official, speaking to reporters on condition of anonymity, said Friday that Mashhadani told Bush when he called to congratulate him on his new post that "the time for violence is over."

The official said the permanent government has an ability to make decisions that have been delayed until now, such as ending subsidies for food and gasoline to make them more market-driven commodities. He said the State Department has teams ready to go to Iraq to help each Cabinet minister tackle issues.