BAGHDAD (Reuters) - Iraq's top Shi'ite, Sunni Arab and Kurdish political leaders announced on Sunday they had reached consensus on some key measures seen as vital to fostering national reconciliation.

The agreement by the five leaders was one of the most significant political developments in Iraq for months and was quickly welcomed by the United States, which hopes such moves will ease sectarian violence that has killed tens of thousands.

But skeptics will be watching for action amid growing frustration in Washington over the political paralysis that has gripped the government of Shi'ite Prime Minister Nuri al-Maliki.

White House spokeswoman Emily Lawrimore congratulated Iraq's leaders on the accord, hailing it in a statement as "an important symbol of their commitment to work together for the benefit of all Iraqis."

The apparent breakthrough comes two weeks before U.S. President George W. Bush's top officials in Iraq present a report that could have a major influence on future American policy in Iraq.

"I hope that this agreement will help Iraq move beyond the political impasse," Deputy Prime Minister Barham Salih told Reuters. "The five leaders representing Iraq's major political communities .... affirmed the principle of collective leadership to help deal with the many challenges faced by Iraq."

Maliki's appearance on Iraqi television with the four other leaders at a brief news conference was a rare show of public unity

BAGHDAD - Sunni politicians applauded goals set down in an agreement hammered out by the country's top leaders under intense American pressure but expressed doubt Monday that the U.S.-backed prime minister would actually see them through.

Prime Minister Nouri al-Maliki and four other senior leaders declared Sunday they had reached a consensus on a number of issues, including freeing detainees held without charge, easing the ban on former Saddam Hussein supporters in government posts, regulating the oil industry and holding provincial elections.

No details were released, and most measures require parliamentary approval.

But in a step toward implementing the deal, U.S. and Iraqi officials announced that coalition forces would increase the number of detainees released during the Islamic holy month of Ramadan, which begins next month.

"Releases will start as early as this week and continue through the end of Ramadan," the U.S. command said in a statement. It did not say how many would be freed.

President Bush hailed the agreement, saying it "begins to establish new power-sharing agreements."

"These leaders ... recognize the true and meaningful reconciliation that needs to take place," Bush said in a brief statement Monday upon arrival in Albuquerque, N.M. "They recognize this is a process. Yesterday's agreement reflects their commitment to work together for the benefit of all Iraqis to further the process."

However, the deal did not convince the main Sunni Arab political bloc to take back the government posts they abandoned this month over differences with al-Maliki, a Shiite.

The Sunni walkout has paralyzed the government ahead of a crucial report to Congress by Ambassador Ryan Crocker and Gen. David Petraeus, which will likely determine the fate of the troubled U.S. military mission in Iraq.

Some key Sunni figures dismissed the agreement as a stalling tactic by al-Maliki to ease pressure from Washington.

U.S. Ambassador Ryan Crocker called the announcement a "positive and encouraging message."