A mortar round slammed into a street in northeastern Baghdad Friday, killing three women when shrapnel hit their home, and soldiers discovered the bullet-riddled bodies of six men wearing handcuffs in western Baghdad, police said.

The mortar struck in the Gaylani neighborhood of Baghdad, but the target was unclear. The Interior Ministry has offices in the area, and a Christian church is nearby. Police said three other people were wounded.

Police said the men found dead in western Baghdad were handcuffed and all were between the ages of 25 and 30.

On the political front, Iraqi leaders trying to form a national unity government resumed talks Friday after taking a few days off to consult with their political blocs over what powers the next prime minister would have over security issues.

Proposals were made Friday, and the issue could be settled by Saturday, Kurdish politician Mahmoud Othman said.

Tensions arose over complaints of U.S. interference in Iraqi political affairs.

A letter from President Bush to Iraq's supreme Shiite spiritual leader, Ayatollah Ali al-Sistani, was hand-delivered earlier this week but sits unread and untranslated in his office, according to a key al-Sistani aide.

The aide — who has never allowed use of his name in news reports, citing al-Sistani's refusal to make any public statements himself — told The Associated Press Tuesday that the ayatollah laid the letter aside because of increasing "unhappiness" over what senior Shiite leaders see as American meddling in Iraqi attempts to form their first, permanent post-invasion government.

The aide said the person who delivered the Bush letter — he would not identify the messenger by name or nationality — said it carried Bush's thanks to al-Sistani for calling for calm among his followers in preventing the outbreak of civil war after a Shiite shrine was bombed late last month.

The messenger also was said to have explained that the letter reinforced the American position that Prime Minister Ibrahim al-Jaafari should not be given a second term. Al-Sistani has not publicly taken sides in the dispute but rather has called for Shiite unity.

The United States was known to object to al-Jaafari's second term but has never said so outright and in public.

But last Saturday, U.S. Ambassador Zalmay Khalilzad carried a similar letter from Bush to a meeting with Abdul-Aziz al-Hakim, leader of the largest Shiite political organization, the Supreme Council for the Islamic Revolution in Iraq.

The al-Sistani aide said Shiite displeasure with U.S. involvement was so deep that dignitaries in the holy city of Najaf refused to meet Khalilzad on Wednesday during ceremonies commemorating the death of the Prophet Muhammad. The Afghan-born Khalilzad is a Sunni Muslim.

Elizabeth Colton, the U.S. Embassy spokeswoman, said Khalilzad had not sought any meetings and simply flew over Najaf and the nearby holy city of Karbala to witness the big processions of Shiite faithful marking the day.

"The ambassador did a flyover to see people on the streets of Karabala and Najaf. The ambassador did not ask to see anyone and did not go into either city," Colton told AP.

The United States is believed to oppose al-Jaafari because of his close ties and strong backing from radical Shiite cleric Muqtada al-Sadr, who has a thousands-strong heavily armed militia that was responsible for much of the violence that hit the country after the Feb. 22 bombing of an important Shiite shrine in Samarra, north of Baghdad.

At a news conference Thursday, al-Jaafari said he had met with Khalilzad a day earlier and that the U.S. ambassador denied remarks attributed to him about the prime minister's candidacy for a new term.

"I don't care much about these matters. I look at the Iraqi people and the democratic mechanisms," al-Jaafari said.

Al-Sadr, who is staunchly anti-American, met with al-Sistani in Najaf on Thursday but emerged without making a statement.

The stalemate over forming a new government for Iraq, in its sixth week after the certification of the vote in parliamentary elections Dec. 15, is focused on al-Jaafari's candidacy, opposed by minority Sunni and Kurdish politicians as well as many moderate Shiites.

The Shiite United Iraqi Alliance nominated him for a permanent four-year term by one vote and with al-Sadr's backing. The Iraqi constitution dictates that the largest parliamentary bloc is entitled to select the prime minister. The Shiite alliance holds 135 seats in the 275-member legislature.

On the outskirts of Baghdad, insurgents set off explosives underneath an oil pipeline Friday. There were no casualties reported, but crews fought the blaze for hours, police 1st Lt. Thair Mahmoud said. The pipeline runs from Beiji, north of the capital, to the Dora district in southern Baghdad, he said.

At least 27 people died in violence on Thursday, including a 4-year-old girl who was killed when a car bomb exploded near the Shiite Ali Basha mosque in Baghdad's eastern Kryaat neighborhood.

The U.S. military reported two deaths. A soldier assigned to the 9th Naval Construction Regiment died Tuesday from wounds sustained in fighting in Anbar province. An airman assigned to the 447th Air Expeditionary Group was killed Thursday near Baghdad. A fellow airman was injured when a roadside bomb exploded as they worked to disarm it, the Central Command reported.