BAGHDAD, Iraq (AP) – Secretary Rice told Iraqi leaders on Thursday they have limited time to settle their differences and that the escalating waves of violence are intolerable.

On a visit five weeks before congressional elections in America, Ms. Rice also insisted the Bush administration has been honest with Americans about the costs and stakes in Iraq.

Administration officials recently have found themselves defending their conduct of the war, and Ms. Rice’s remarks reflected the political toll for the White House from an unpopular conflict.

“This is really hard going,” Ms. Rice told reporters during her stop in the Iraqi capital. “Not only do I believe that the president has been clear with the American people that this is a struggle, he’s been clear with the American people why he thinks it’s a struggle that needs to be waged.”

After meetings in the Mideast with Arab and Israeli leaders, the top American diplomat came to Iraq to tell sometimes squabbling leaders they have a short window to resolve disputes that she said are spurring sectarian and insurgent violence.

While killings among Iraqis have not abated, American casualties also have spiked recently.

Car bombs killed four people and wounded 28 in Baghdad on Thursday. At least 21 U.S. soldiers have died since Saturday; most were in Baghdad amid a massive security sweep by American and Iraqi forces.

Ms. Rice said the American role is “to support all the parties and indeed to press all the parties to work toward that resolution quickly because obviously the security situation is not one that can be tolerated and it is not one that is being helped by political inaction.”

Ms. Rice met with Prime Minister al-Maliki and other officials as the sectarian cycle of revenge killings between Shiites and Sunnis threatened to undermine his government. Shiite and Sunni parties in Mr. al-Maliki’s coalition accuse each other of backing militias.

Mr. al-Maliki told Iraqi state TV on Thursday that the country is in the final stage of “confronting the security challenge” and that security would be achieved “within the two or three months to come.”

Ms. Rice said Iraqis themselves must settle difficult problems such as the division of oil wealth, possible changes to the constitution and the desire for greater autonomy in various regions.

“Obviously the security side and the political side are linked,” Ms. Rice told reporters.

In an interview with The Associated Press, Mr. al-Maliki said that once the Iraqis work out their differences, “the political solution must be obligatory, one that all parties adhere to. The presence of parties with militias in the government is not acceptable.”

Ms. Rice described the task as “the ability to get everybody to understand precisely how their interests are going to be represented and how their interests are going to be served in this political process.”

Mr. al-Maliki made curbing Baghdad violence his first priority after taking office in the spring. But curfews and other measures have failed to make much difference.

On Monday, Mr. al-Maliki announced a security plan to unite the feuding parties, creating local committees in which Sunnis and Shiites will work together to manage efforts at quelling the violence on a district-by-district level.

Contentious details of the plan must be worked out, and Shiite and Sunni parties twice have put off negotiations.

“This is, of course, a time of challenge for the Iraqi people,” Ms. Rice said after a brief meeting with Mr. al-Maliki. “They are a committed people and we know they will overcome these challenges.”

In addition to talks with Mr. al-Maliki and President Talabani, Ms. Rice also saw Sunni leaders.

Ms. Rice’s plane circled the Baghdad airport for 35 minutes before landing because of a threat from “indirect fire” – mortar rounds or rockets – in the airport area, State Department spokesman Sean McCormack told reporters.

In Washington, Senate Democrats issued a press release Thursday calling attention to the growing number of American casualties and a record level of bomb attacks in Baghdad.

In AP-Ipsos polling last month, more than half of Americans said America was losing ground in Iraq. About 40 percent approved of President Bush’s job performance.

Ms. Rice disputed that the administration has been less than candid about Iraq. Now in its fourth year, the conflict has claimed more than 2,700 American lives and cost more than $300 billion.

A new book by journalist Bob Woodward about the wartime White House, asserts that the administration routinely has understated the difficulties and fudged hard truths in Iraq.

“I would say, go back and look at any presidential speech in the last year and the discussion of the fact that this is very tough going is in there,” Ms. Rice said.