BAGHDAD - Suicide bombers killed 13 people in a pair of attacks yesterday around the Sunni city of Ramadi in what local officials said was part of a power struggle between al-Qaeda in Iraq 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 western Baghdad, including 17 in the Amil neighborhood, where Sunni politicians have complained of renewed attacks by Shiite militiamen, according to a police official who spoke on condition of anonymity.

Sunni complaints prompted the country's Sunni vice president, Tariq al-Hashemi, to threaten to leave the Shiite-dominated government unless key, but unspecified, amendments to the constitution are made by next Tuesday. Hashemi, in an interview with CNN, also said he turned down an offer by Bush to visit Washington until he can count more fully on U.S. help, CNN said on its Web site.

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 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, Police Col. Tariq Youssef said.

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 police officers, 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 al-Qaeda for the attacks.

"They committed this crime because we have identified their hideouts and we are chasing them," said Sheikh 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 al-Qaeda group said.

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

The 34 also included the police chief of Samarra, Col. Jalil Nahi Hassoun, who was killed Sunday in an attack on police headquarters.

At least five al-Qaeda fighters were killed in the fighting in Samarra, a U.S. military official told the Associated Press, speaking on condition of anonymity.

Also yesterday, the military said a U.S. soldier had been killed by small-arms fire in western Baghdad the day before.

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

Maliki told Bush of the need to maintain cooperation between U.S. and Iraqi forces as they continue their crackdown, the prime minister's office said in a statement.

White House spokesman Tony Snow said Bush and Maliki spoke about the Iraqi leader's push for political reconciliation in his country, an area considered vital to greater stability.

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

Troop Survey Has Petraeus 'Greatly Concerned'

The top U.S. commander

in Iraq said yesterday

that he was "greatly concerned" by a recent survey that found many troops in Iraq would not report a member of their unit for killing or injuring an innocent civilian.

Gen. David Petraeus called for a "redoubling of our education efforts" to identify potential abuses among soldiers.

"We can never sink to

the level of the enemy," Petraeus said by video link from Baghdad.

"We have done that at times in theater, and it has cost us enormously" - referring to the treatment of prisoners

at the Abu Ghraib facility west of Baghdad.

- Associated Press

Read the full survey via EndText