BAGHDAD - U.S. warplanes attacked suspected militiamen wielding shoulder-fired rockets Saturday in the second day of fierce fighting between U.S. and Iraqi forces and Shiite gunmen south of Baghdad, U.S. and Iraqi officials and witnesses said.

At least one civilian was killed and five were seriously wounded when an American tank fired on their house in Diwaniyah, 128 kilometres south of Baghdad, Iraqi police and hospital officials said. The victims had to be pulled from the rubble of their home, and evacuated to Diwaniyah hospital, police said.

The U.S. military had no immediate comment Saturday on any casualties among civilians or soldiers in Diwaniyah.

In Baghdad, two U.S. soldiers were killed and seven were wounded by two separate roadside bombs in Baghdad Friday.

One U.S. soldier was killed and four were wounded in an attack with an armor-piercing explosively formed projectile, or EFP, the military said in a statement.

The U.S. has blamed Iran for supplying Shiite militias in Iraq with the powerful weapons, which hurl a molten, fist-sized copper slug capable of piercing armored vehicles.

Saturday's statement did not say whether the soldiers were on foot or in a vehicle when they were hit.

Another roadside bomb killed one U.S. soldier and wounded three others Friday in western Baghdad, the military said in another statement. That unit had disarmed a car bomb rigged to explode just days earlier, the military said.

An average of four U.S. soldiers died or were killed in each of the first five days of this month. If that pace were to continue, the monthly toll would be 120 and the highest since November 2004, when U.S. forces were besieging Fallujah, then another Anbar province insurgent stronghold.

U.S. forces also killed Saturday one suspect and captured eight others in raids in Baghdad and south of Ramadi, the provincial capital of Anbar, the military said.

The man killed had been identified as the leader of a terror cell that planted car bombs targeting U.S. troops and civilians, the U.S. military said in a statement.

On Saturday, Foreign Minister Hoshyar Zebari said that ministers from Iraq's neighboring countries, the five permanent members of the U.N. Security Council and industrialized nations will hold a meeting in Egypt early next month.

The meeting, which was supposed to be held in Turkey, follows an international conference held in Baghdad last month in which envoys from Iran and the U.S. spoke directly to one another for the first time in years.

The meeting will be held in the Egyptian Red Sea resort of Sharm el-Sheik on May 3-4, Zebari said.

American troops swept into the troubled, predominantly Shiite city of Diwaniyah before dawn on Friday, killing three militia fighters and capturing 27 in the first day of the assault, the military said. The attack -- named "Operation Black Eagle" -- targeted gunmen loyal to anti-American cleric Muqtada al-Sadr. Fighting continued Saturday.

On Friday, a spokesman for al-Sadr's political movement in Baghdad denied there was any exchange of fire in Diwaniyah.

"There is only an unprovoked attack by invading American troops," spokesman Haider al-Natiq told Al-Arabiya television.

But on Saturday, al-Sadr's office in Diwaniyah suggested the fighting was not one-sided and claimed gunmen destroyed three American vehicles and seized a robot used to explode roadside bombs. U.S. officials could not confirm that claim.

Dozens of people have been killed in Diwaniyah during the past weeks and the attacks have been blamed by residents on the Mahdi Army, al-Sadr's militia.

Many women, accused by the hard-line and fundamentalist militiamen of violating their interpretation of Islamic morality, are among the dead. Police, residents who work for coalition forces at a nearby Polish army base, journalists and the wealthy, who have been kidnapped for ransom and then killed also have been targeted.

Saturday's airstrike grew out of a tip from residents who told Iraqi military officials that militiamen were operating in the area, the U.S. military said in a statement. The strike targeted "illegally armed militiamen using shoulder-fired rocket propelled grenades," it said.

In other violence, a roadside bomb exploded next to a joint American-Iraqi army patrol early Saturday on a highway leading into Annah, 281 kilometres northwest of Baghdad. Two Iraqi soldiers were killed and two were wounded, the Iraqi military said.

Police in Fallujah, west of Baghdad, reported finding four bodies in the center of the city. The corpses showed signs of torture and had been shot in the head.

Also Saturday, the U.S. military announced 14 suspects and a large weapons cache were captured earlier in the week in western Baghdad's Yarmouk neighborhood. It said security operations continued in the area. At least 14 men were detained and explosives, bomb-making materials, handguns and mortars were found.