In the Baghdad incident, the Red Crescent society reported that a maternity hospital was struck.
There were conflicting reports of what allegedly caused civilian deaths in Hillah. Iraqi officials said 33 people were killed in a helicopter attack, but some reporters alleged that cluster bombs had killed several civilians. The Pentagon acknowledged that it had dropped six cluster bombs on central Iraq on Tuesday.
The International Red Cross said one of its teams saw 280 wounded civilians in a Hillah hospital. "It appears that this was the result of heavy fighting and bombardment in the course of the previous 48 hours in and near the town of Hindiya near Hillah," a statement said.
The allegations could test the assertion, which the Pentagon has made daily and initial evidence from the field appears to support, that the bombing campaign is targeted solely at government targets and strives to avoid civilian casualties.
Central Command says all the munitions used in the campaign so far have been laser- or satellite-guided.
"We are very deliberate … about our targeting, about our weapon selection to achieve a desired effect," Brig. Gen. Vincent Brooks, a Central Command spokesperson, said. "The strikes have been precision strikes throughout."
Central Command and the Pentagon have insisted throughout the campaign that any civilian casualties were the result of the Iraqi military's tactics.
"Our view is the blood is on the hands of regime," Brooks said Tuesday.
Last week, the U.S. was twice accused of hitting civilian areas in Baghdad. On Wednesday, Iraq said 14 were killed in a strike on a market.
Brooks said that an extensive investigation that examined the timing and targeting of U.S. missile launches and the size and shape of the crater at the scene led Central Command to conclude that the marketplace bombing was not the fault of U.S. bombing.
"There's absolutely nothing that joins that to coalition action," he said.
Another explosion in Baghdad on Friday was said to have claimed some 60 lives.
Central Command is also investigating an Iraqi allegation that the U.S. bombed and destroyed two buses carrying human shields.
Probes are also under way into two other incidents. In the first, soldiers killed at least seven women and children when their van failed to stop at a U.S. checkpoint.
According to Central Command, the soldiers fired warning shots, then fired at the engine, and only shot into the vehicle as a last resort. But a Washington Post reporter said an officer on the scene indicated that soldiers had waited too long to fire warning shots.
A correspondent for Knight Ridder Newspapers on Wednesday quoted surviving family members as saying they had decided to flee toward U.S. lines because they thought a leaflet dropped by American helicopters said it would "be safe."
Bakhat Hassan who said he lost two daughters and a son, all 5 or younger, his parents, two older brothers, their wives and two nieces said U.S. soldiers at an earlier checkpoint had waved them through. As they approached a checkpoint 25 miles south of Karbala, they waved again at American soldiers. Those soldiers fired.
"I saw the heads of my two little girls come off," said Hassan's wife, Lamea, 36.
The Hassans decided to make the journey after an American helicopter dropped fliers over their farming village that showed a drawing of a family sitting at a table, eating and smiling, with a message written in Arabic.
Sgt. 1st Class Stephen Furbush, an Army intelligence analyst, said the message read: "To be safe, stay put."
But Hassan said he and his father thought it just said, "Be safe." To them, that meant getting away from the helicopters firing rockets and missiles.
"A miscommunication with civilians," said an Army report written Monday night.
U.S. officials originally gave the death toll as seven in the incident, while reporters at the scene placed it at 10. Hassan's father died at the Army hospital later; Hasan said that made the toll 11.
The shooting followed a suicide attack Saturday that killed four U.S. soldiers at a checkpoint. Because of that incident, the Post reported, troops in the field planned more vigilance in dealing with civilians.
Central Command says there has been no change in rules of engagement since the attack. However, Brooks points out that: "There will always be tactical adjustments that are made on the battlefield."
In the second incident near Najaf, an Apache helicopter wounded a civilian when it fired on his truck.
The BBC, meanwhile, reported that a hospital in Nasariyah had logged 250 civilian fatalities since the war began. In addition to the accuracy of the report, the circumstances of the deaths were unclear. U.S. troops have reported combat with irregular troops dressed as civilians, and reported that other noncombatants have been used as human shields.
Besides the possible civilian casualties, the humanitarian situation seemed stable. Water service has been restored to Basra and there was no evidence of disease there, despite several days without water service. Relief supplies have begun flowing into the port at Umm Qasr.
Food was never a major concern for the Red Cross because the Iraqi government issued double rations and the long lead-up to war gave people time to build up their own stockpiles.
But the Red Cross said it was "increasingly concerned about the situation in towns such as Najaf, Karbala and Nasariyah, which have been the scene of heavy fighting for days now and which neither international humanitarian organizations nor journalists have been able to visit."