Coalition warplanes blasted new targets in and around Baghdad Tuesday while ground fighting continued south of the capital. Meanwhile, U.S. officials have expressed regret for an incident near the central town of Najaf Monday in which at least seven Iraqi civilians were killed at a military checkpoint.
The overnight targets in Baghdad included Iraq's Olympic Committee headquarters and one of Saddam Hussein's palaces. Witnesses said the bombing attack was among the most intense of the war so far.
The head of the Iraqi Olympic Committee is Saddam Hussein's oldest son, Udai, and western intelligence agencies say he has been running a torture chamber inside the building for years.
Other air attacks continue to target Republican Guard units blocking the southern approaches to Baghdad.
Iraqi Information Minister Mohammed al-Sahaf says 19 civilians were killed and more than 100 people wounded in the recent wave of bombings. But he told reporters in Baghdad that the government remains defiant in the face of coalition attacks.
"They are achieving nothing," Mr. al-Sahaf said. "They are suffering from casualties. Those casualties are on the increase, not decrease."
Mr. al-Sahaf also says U.S. warplanes attacked two buses carrying human shields from Iraq to Jordan, but a U.S. military spokesman said he had no information on that.
Also Tuesday, U.S. Marines waged what was described as "bloody street-to-street" fighting in and around the central Iraqi town of Diwaniya and took at least 20 Iraqi prisoners.
VOA correspondent Alisha Ryu is with U.S. troops in central Iraq. She says coalition forces are stepping up preparations for a major ground assault on Baghdad.
"Yes, there is increased amount of activity," she said. "There is a great deal of preparation going on. It's been ongoing for over a week now and I think there are some indications now that this may be sooner rather than later."
Meanwhile, U.S. military officials at the central command headquarters in Qatar have expressed regret for an incident that led to the deaths of at least seven Iraqi civilians Monday and say it is now under investigation.
U.S. troops shot at a van loaded with civilians, including women and children, when it failed to stop as it approached a military checkpoint near Najaf. U.S. officials say they fired warning shots but the van refused to stop.
U.S. troops are on heightened alert at the checkpoints following Saturday's suicide attack in which four Americans died.
Tuesday's military briefing in Qatar was dominated by questions about the incident.
"Our checkpoints have to remain alert and vigilant to any type of threat that would approach that is being protected and secured," said U.S. Army Brigadier General Vincent Brooks. "We have not had a change in rules of engagement in recent days. There is increased vigilance because of the tactics that we have seen throughout the battlefield by the regime and the death squads that are out there."
General Brooks says he regrets the loss of civilian lives but added that they "remain unavoidable" as they have throughout the history of warfare.
Despite the incident, General Brooks says Iraqi civilians continue to help coalition forces target regime supporters in central and southern Iraq. And he says it is the Iraqi government that must bear the blame for civilian casualties.
"We know that the regime would like to see as much difficulty placed between our efforts and their eventual departure and demise as can be made," he said. "And if they can put the Iraqi population between themselves and us, we have seen repeated occasions that they are willing to do that. In fact, this regime has shown they will go to just about any extent to protect themselves."
General Brooks also says a recently-captured senior Iraqi general is cooperating with coalition forces. The Iraqi officer is said to have provided tactical information of use to coalition forces.
In other developments, Kuwait says an incoming Iraqi missile was shot down by a U.S. Patriot missile battery early Tuesday. Iraq has fired more than a dozen missiles at Kuwait since the war began.
Also, two U.S. Navy pilots are safe after their plane veered off the flight deck of the U.S. aircraft carrier Constellation. They were plucked from the sea by a rescue helicopter.
On the diplomatic front, U.S. Secretary of State Colin Powell heads to Turkey and later Brussels on a trip aimed at smoothing relations with Ankara and other NATO allies that have been strained by the war in Iraq.
On Monday, Secretary Powell accused Iraq of widespread human rights violations as part of the State Department's annual human rights report.