BAGHDAD - Suicide bombers killed 13 people in a pair of attacks yesterday around the Sunni Arab city of Ramadi in what local officials said was part of a power struggle between al Qaeda and tribes that have broken with the terror network.

In all, at least 68 people were killed or found dead nationwide yesterday, police said. They included the bullet-riddled bodies of 30 men found in Baghdad - the apparent victims of sectarian death squads.

All but two were found in west Baghdad, including 17 in the Amil neighborhood where Sunni politicians have complained of renewed attacks by Shiite militiamen, a police official said.

The first of the Ramadi-area attacks happened about noon in a market on the northwest outskirts of the city, killing eight people and wounding 13, said police Col. Tariq Youssef.

About 15 minutes later, police at a nearby checkpoint spotted a second car bomb and opened fire, but the driver was able to detonate the vehicle, Youssef said. Five people, including two policemen, were killed and 12 were wounded, Youssef said.

The attacks occurred in areas controlled by the Anbar Salvation Council, an alliance of Sunni tribes formed last year to drive al Qaeda from the area. Council officials blamed the attacks on al Qaeda.

"They committed this crime because we have identified their hideouts and we are chasing them," said Sheik Jabbar Naif al-Dulaimi.

In a Web statement yesterday, an al Qaeda front organization, the Islamic State of Iraq, warned Sunnis against joining the government security forces - a move supported by the Salvation Council.

"We tell every father, mother, wife or brother who does not want to lose a relative to advise them not to approach the apostates and we swear to God that we will use every possible means to strike at the infidels and the renegades," the group said.

The Islamic State also claimed responsibility yesterday for attacks that killed 34 people over the weekend - including six U.S. soldiers and a Russian embedded photojournalist who died in a roadside bombing in Baqouba.

Also yesterday, the military announced that a U.S. soldier was killed by small-arms fire in western Baghdad the day before, bringing to nine the number of American personnel slain Sunday.

The security situation in the capital figured high in talks between Prime Minister Nouri al-Maliki and President Bush, who spoke yesterday in a video conference.

White House spokesman Tony Snow said Bush and al-Maliki spoke about the Iraqi leader's push for political reconciliation, which is considered vital to bring stability.

The two leaders spoke for about 25 minutes with staff members in attendance, then for another period of time one-on-one, Snow said.

Al-Maliki, a Shiite, reiterated his determination to work with Sunni leaders, Snow said.

In an interview with CNN, Iraqi Vice President Tariq al-Hashemi said he would lead a Sunni walkout from the Cabinet and parliament if changes are not made to the constitution by May 15.

A walkout by the Sunnis, who control 44 of the 275 parliament seats and five Cabinet posts, would plunge Iraq into a political crisis.

The International Committee of the Red Cross announced yesterday that it would increase its operations to provide food, water and medical treatment for hundreds of thousands of Iraqis who have fled their homes but remain in the country.

"This conflict is inflicting immense suffering on all Iraqis," Beatrice Megevand-Roggo, head of the organization's Middle East operations, said in Geneva. "Civilians are bearing the brunt of the relentless violence."

Hundreds of thousands of other Iraqis have fled to Jordan and Syria.

Late yesterday, the Islamic State of Iraq said it had captured five Iraqi army officers and four policemen in Diyala province and threatened to kill them unless authorities freed Sunni women held in Iraqi prisons and turned over "all those who killed our people" in the northern city of Tal Afar.

No deadline was given. *