Three US soldiers have been killed in an ambush near Saddam Hussein's home town of Tikrit, the latest in a continuing series of attacks on Americans in Iraq.
Two soldiers were wounded in the Tikrit attack
Two soldiers were injured in a separate attack on a convoy in the town of Khaldiyah, west of Baghdad, with unconfirmed reports speaking of a number of men killed.
President George W Bush has said that a new United Nations resolution on Iraq is unlikely to be approved soon.
His administration had been hoping that the resolution, which calls for more money and troops, could be passed before the president addresses the UN General Assembly next Tuesday.
The BBC's Justin Webb in Washington says the president's search for diplomatic progress comes as his domestic critics mount ever more ferocious attacks on US policy in Iraq.
Democrat Senator Edward Kennedy called the original case for war "a fraud made up in Texas", President Bush's home state.
Germany and France have demanded the swift transfer of power in Iraq from the US-led coalition to Iraqis.
Speaking after talks in Berlin with his German counterpart Gerhard Schroeder on Thursday, French President Jacques Chirac said the process should be led by the United Nations and take place "as quickly as possible... [within] months, not years".
Wide differences with Washington remain, and France has still not pledged support for the new US resolution at the UN.
Meanwhile, US Secretary of
State Colin Powell has dismissed French proposals for an early transfer of power to Iraqis as "totally unrealistic".
The US soldiers died as they were investigating a suspected launch site for rocket-propelled grenades in the village of al-Ouja, just south of Tikrit.
They came under small arms fire, and three were killed, with another two injured.
Earlier on Thursday, there was a gun battle lasting several hours after an ambush near Khaldiyah.
A truck transporting troops was blown up by an explosive device on a road and soldiers were fired on as they tried to evacuate casualties, Iraqi sources said.
US troops are hunting supporters of Saddam Hussein
During the firefight, a car belonging to the Associated Press news agency was targeted by American soldiers, but journalists ran to safety before it was shot at by tank and machine gun fire.
In another incident near Khaldiyah, a bomb hit another convoy, engulfing one vehicle in flames.
Some witnesses spoke of up to eight Americans being killed, but the US military only confirmed two injured, without specifying in which incident the injuries occurred.
Khaldiyah is part the so-called "Sunni Triangle" where support for ousted dictator Saddam Hussein is strongest.
"With our blood, with our soul, we will sacrifice for you Saddam," demonstrators were reported to have chanted after US tanks left, as well as: "Saddam is the glory of my country."
In Falluja, US troops reportedly opened fire, killing a teenage boy, as guests at a wedding party shot their guns into the air,
Witnesses said soldiers, believing they were under attack, formed a circle and began shooting.
At least four people were injured, witnesses said.
The reported incident fuelled tensions in the town, where opposition to America's presence in Iraq is strong.
It comes days after the US apologised for accidentally shooting dead eight Iraqis and a Jordanian in Falluja, a stronghold of supporters of ousted Iraqi leader Saddam Hussein.