BAGHDAD, Iraq, June 12 - Iraq moved further toward a political stalemate today, as Shiite political leaders agreed on what they said was a compromise to include Sunni Arabs in the writing of this country's constitution, and Sunnis flatly rejected the offer.
In an attempt to defuse a political confrontation with this country's embittered Sunni Arabs, the Shiite-led constitutional committee of the Iraqi parliament, met for several hours today and decided to give Sunnis 15 seats with full membership on the 55-member committee and an additional 10 adviser positions. The offer was aimed at satisfying the demands of Sunnis, who have insisted that they get at least 25 seats.
Sunnis, about a fifth of Iraq's population, are thinly represented in this country's parliament, because they refused to vote in national elections in January. American officials have been pressing Shiite and Kurdish leaders to give Sunnis a greater role in politics, and today's agreement was their effort to satisfy that demand.
"I think they will accept because we are offering everything for them," said Bahaa al-Aaraji, a Shiite political leader who is a senior member of the committee.
But two Sunni political leaders interviewed by telephone shortly after the decision said bluntly that it would be rejected by the majority of Sunni Arabs, whose fringes, which include former Baath Party members and militant Islamists, drive the radical insurgency here.
"Arab Sunni will not accept this number," said Mejbel al-Sheikh Isa, a member of the National Dialogue Council, a Sunni group that has urged political involvement. "Advisers? It's not our mission. When we say participation we mean real participation.
"If we will not participate in the constitution, that means an increase of violence in Iraq."
But even before today's political decision, the attacks had continued to take lives here. The American military announced today the deaths of four marines, all killed by roadside bombs on Saturday. They were killed in two different vehicle accidents in al-Anbar, a Sunni Arab province in western Iraq that strongly supports the insurgency.
And in another disturbing discovery of corpses, an official in the Interior Ministry said the Iraqi police had found 20 decomposed bodies in al-Nahrawan, an area south of Baghdad, buried in a field that was used for shooting practice in the old Iraqi Army.
In a sad but familiar scenario, the bodies bore signs of torture. They were dressed in plain clothes and appeared to have been killed four or five months ago, the official said. The police had yet to identify the bodies
Even so, in a measure of how politicized the killing has become here, a hard-line Sunni Arab organization, the Muslim Scholars Association, said the bodies were of Sunni men.
Authorities found two other groups of bodies today. In Huriyah, a Shiite area in northwestern Baghdad, three bodies were found shot in a 1984 Toyota, and later today, three more were found in eastern Baghdad, in an area close to a Shiite slum.
The bloodshed in Baghdad had abated in previous weeks, as Iraqi forces tightened security in and around the city in a large-scale offensive, but surged again late Friday, when a car bomb exploded outside a health center here killing at least 10 people.
Though the constitutional committee met today to discuss seats for Sunni Arabs, they will not formally make the offer until their next meeting with them, which is scheduled for Thursday, delaying any formal acceptance or rejection of the offer for nearly a week.
The committee is under pressure to complete a draft of the constitution by Aug. 15, so the country can vote on it in October, and hold new elections in December. Prime Minister Ibrahim al-Jaafari has said recently the deadlines would not be extended.
One of the reasons it has been so difficult to agree is that Sunnis are a disparate and sometimes competing group. In the last meeting, committee members said each group came with different lists of names, making for unwieldy negotiations. And within the groups themselves, hard-liners refuse to agree to what more moderate Sunni Arabs accept.
Tarik al-Hashimy, a leader of the Iraqi Islamic Party, said in a telephone interview last night that the less flexible Sunni Arabs in the parties would reject today's proposal.
"We have enough hard-liners" in the Sunni Arab parties, he said, and "we have enough problems convincing them to accept the figure of 25 seats."
Meanwhile, an outspoken supporter of the war, Representative Walter B. Jones, a Republican from North Carolina, said in an interview today on the ABC News program "This Week" that he had changed his position and called for fixed a timetable for withdrawal of troops here.
The remarks came two weeks after military commanders told a congressional delegation visiting Iraq that it would take about two years before enough Iraqi security forces were sufficiently trained to allow the Pentagon to withdraw large numbers of American troops.
In other violence here, three mortar rounds struck near a house in Baghad, where a funeral of a relative of Rashid Feleih, a police commando officer, was taking place. One person was killed and two others were wounded, the ministry official said.
The bright spot today was the announcement of the release of Florence Aubenas, a journalist for Liberation, and her Iraqi driver, Hussein Hanun al-Saadi, who had been kidnapped in Baghdad on Jan. 5.