Insurgents launched a deadly coordinated attack on an American combat patrol, detonating a roadside bomb, then firing guns and rocket-propelled grenades at the soldiers, the U.S. military said Friday. Five troops were killed.
Seven soldiers were wounded in the attack on Thursday in southern Baghdad and were evacuated to a military hospital; one has since returned to duty, the military said.
"It was a very violent attack and we thought it did show a level of sophistication that we have not often seen so far in this campaign," Army Maj. Gen. Joseph F. Fil Jr., commanding general of Multi-National Division Baghdad and First Cavalry Division, said Friday.
As U.S. troops have gone through Baghdad in areas previously overrun by militants, "they are starting to fight very hard and that's what we saw yesterday."
The deaths brought to 99 the number of U.S. troops to die in Iraq this month, according to an Associated Press count. The toll for the past three months — 329 — made it the deadliest quarter for U.S. troops in Iraq since the war began in March 2003.
At least 3,576 members of the U.S. military have died since then, according to AP figures. The number includes seven military civilians. At least 2,936 died as a result of hostile action, according to the military's numbers.
Meanwhile, radical cleric Muqtada al-Sadr postponed a Shiite march to a bombed shrine north of Baghdad that was scheduled for July 5, an aide said.
"Muqtada al-Sadr has decided to postpone the march to Samarra for several reasons, including the government's inability to secure the route and many officials' appeals for a postponement," said Sheik Asad Al-Nassiri, an aide to the cleric. He made the announcement during a Friday sermon in nearby Kufa.
Sunni organizations and government officials had urged al-Sadr to cancel the march to the Askariya shrine in Samarra, which was bombed for a second time earlier this month, fearing it would escalate sectarian violence that already has claimed thousands of lives.
Al-Sadr had said the march was aimed at bringing Shiites and Sunnis closer together and breaking down the barriers imposed by the Americans and Sunni religious extremists.
Also Friday, the British military issued a statement saying both of its two main bases came under attack from mortars or rockets in the past 24 hours, but there were no casualties or damage.
Britain maintains a force of about 5,500 troops based mainly on the fringes of Basra, Iraq's second-largest city, 340 miles southeast of Baghdad.
In other violence, Iraqi police said at least six Iraqi soldiers were killed and five wounded when a suicide truck bomb exploded at their army post north of Baghdad. Two civilians were also killed in a barrage of gunfire that followed, they said.
The blast went off at a railway station in Mishada, a town 20 miles north of the capital, an officer said on condition of anonymity because he was not authorized to release the information. It destroyed half the building and ignited a fire, he said.
Most of the victims had been setting up a new checkpoint near the station, along the Baghdad-Mosul highway, police said.
In other developments, Iraqi police said a bomb exploded under an oil pipeline south of Baghdad on Friday, spilling crude oil and sparking a huge fire.
The explosives were planted under a stretch of pipeline in the Mowehlah area of Haswa, a town 30 miles south of the Iraqi capital, a police officer said on condition of anonymity because he was not authorized to release the information.
The pipeline transmits crude oil from Iraq's southern oil fields to the Dora refinery in Baghdad.
The blast ignited a huge fire around 5 a.m., the officer said. By midday, firefighters were still struggling to extinguish the flames, which were fueled by a continuing leak of oil from the pipeline, he said. Workers also were looking for a way to temporarily cut off the oil flow, until a repair could be made, the officer added.