Prime Minister al-Maliki and his government should be voted out of office by the country’s Parliament because he is incapable of bringing about political unity, the U.S. Senate’s Armed Services Committee chairman, Carl Levin, said.

Mr. Levin, a Michigan Democrat, said he reached that conclusion after a two-day trip to Iraq last week, which coincided with a series of high-level meetings among Iraqi leaders aimed at reaching political agreements to ease sectarian tensions.

Mr. Levin said those meetings, after showing some initial promise, ended inconclusively and reinforced his judgment that Mr. Maliki couldn’t lead his country to higher political ground.

“I have reached the conclusion that this government is not going to be able to make the compromises so essential to ending the violence,” Mr. Levin told reporters today in a conference call from Tel Aviv, where he traveled after Iraq.” The Iraqi Parliament should have the wisdom to replace it.”

Senator Warner of Virginia, a leading Republican who accompanied Mr. Levin to Iraq, expressed pessimism in a joint statement about the possibility of compromise among Iraqi politicians, while not indicating he had lost confidence in Mr. Maliki.

White House spokesman Gordon Johndroe, while not responding directly to Mr. Levin’s comments, urged Mr. Maliki and other Iraqi leaders to “reach a political accommodation among the various parties” and expressed confidence that he and his colleagues “will be able to get this important work done.”

Mr. Levin, who opposed President Bush’s decision to increase American troop levels in Iraq, said he saw evidence that the buildup was producing positive results by improving security in some parts of Iraq.

Still, he said, the larger purpose of the so-called surge — to provide Iraqi leaders with “breathing space” to reach political compromises — was being squandered by Iraqi leaders.

“Those leaders have not grasped that opportunity,” he said. “They continue to fritter it away.”

Mr. Levin said the Iraqi Parliament has the authority to oust Mr. Maliki through a no-confidence vote, and that such a vote could be forced if 25% of the lawmakers sign a petition requesting it. He declined to speculate on a possible successor to the prime minister.

An aide to Secretary of State Rice said last week that ending political squabbles in Iraq must become the priority as violence recedes in some areas due to American military reinforcements.

Ambassador David Satterfield, who advises Ms. Rice on Iraq, said in an interview that the quest for political agreement “needs to move forward urgently.”

America is trying to get the United Nations more involved as a broker among Iraqi factions to broaden international support for the country.

Mr. Levin said he still believes that America should begin reducing its forces in Iraq because that is the only way to pressure Iraqis to move toward political compromises.

“I don’t know any other way to force Iraqi leaders to do that, other than to say that the open-ended commitments are gone,” said Mr. Levin, who has co-sponsored legislation that would require a withdrawal to begin within 120 days of the measure’s adoption. Republican senators succeeded in blocking the measure last month.

Mr. Levin said the Iraqi army was showing signs of improved combat capability and was therefore able to assume more responsibility for the country’s security. He said he didn’t know whether Mr. Warner, a former chairman of the armed services panel, shared his view that Mr. Maliki should be ousted. A Warner spokesman, Jonathan Murphy, said the senator was traveling and unavailable for comment on Mr. Levin’s remarks.

In their joint statement issued shortly before Mr. Levin spoke, the two senators said they were “not optimistic” that the Iraqi government will take the steps necessary to bring peace to the country, even as added American troops have reduced violence.

In their statement, Messrs. Warner and Levin said the American buildup has “produced tangible results in making several areas of the capital more secure” and has fulfilled its goal of giving Iraqi politicians the opportunity to reach new agreements. They said they were “not optimistic about the prospects for those compromises” and viewed the recent high-level meetings as possibly “the last chance” for the current government.