US and UK forces have captured key areas of southern Iraq as they advance on the capital Baghdad.
Coalition forces have encountered resistance
The US military says the vanguard of the coalition force is now beyond the city of Nasiriya, after taking control of two key crossing points on the Euphrates river and the nearby airfield of Tallill.
Iraqi TV reported fighting with US troops on Saturday evening near the town of Najaf, 160 kilometres (100 miles) south of Baghdad.
The southern oilfields, including those around the city of Basra, are said to have been secured and a three-mile-long convoy of US Marines has moved out of the area to join the forward advance.
A fourth consecutive night of coalition air raids on Baghdad has begun and much of the city has been plunged into darkness.
Correspondents say explosions were heard soon after sunset, followed by a major bombardment of the city.
The BBC's Andrew Gilligan in Baghdad says it is the first assault on the city's power supplies.
Shortly after 2100 GMT there were also reports of explosions and tracer fire in the northern Iraqi city of Mosul.
Earlier, the commander of the military operation in Iraq, US General Tommy Franks, said the military campaign was "unlike any other in history" and that victory would be achieved with overwhelming force.
At his first news conference since the war began, General Franks said special forces operating behind enemy lines had played a key role in the initial stages of the operation, particularly in preventing the Iraqis from sabotaging southern oil installations.
However, at least nine oil wells are said to have been set on fire by fleeing Iraqi forces.
And despite coalition claims that up to 2,000 Iraqi soldiers have surrendered, American and British troops in and around both Basra and Nasiriya have continued to meet stiff resistance in some areas.
US war plans suffered a setback as the Pentagon finally abandoned hope of persuading Turkey to allow troops through to open a northern front in northern Iraq.
Iraq says 200 people were injured and three killed in Friday's air raids
Forty military supply ships which have been waiting for weeks in the Mediterranean off the coast of Turkey are now to be sent through the Suez Canal to the Gulf.
Iraqi officials say Friday night's escalated air strikes on Baghdad killed three civilians and injured hundreds more.
The International Committee of the Red Cross says its workers saw at least 100 wounded people, 20 of them women, in a city hospital on Saturday morning - but added that it was unclear whether they were civilians or members of the military.
A presidential palace was set ablaze during the attacks, as were offices of the foreign ministry and the deputy prime minister.
Earlier on Saturday, the first daylight air raids hit Baghdad, leading its Iraqi defenders to set pools of oil around the city on fire to confuse American and British pilots.
In other developments:
Second helicopter crash
- Turkey denies sending commandos across the border into northern Iraq
- US missiles are fired at an area close to the border with Iran held by Islamic militants, the Ansar al-Islam
Pentagon says so far no Scud missiles launched in Iraq conflict
- United Nations officials say up to 450,000 people have fled towns in northern Iraq ahead of any conflict
- Anti-war rallies are held around the world
- Sheikh Muhammad Sayyed Tantawi, imam of the historic al-Azhar mosque in Cairo, says the war in Iraq is not a confrontation between the Muslim and Christian worlds
- In his first public comments since the beginning of attacks, Pope John Paul II says the war "threatens the fate of humanity"
- British news organisation ITN reports that one of its war correspondents, a cameraman and their translator are missing after
they came under fire in southern Iraq
- Iran's official news agency says rockets have landed on its side of the Iraq border, adding that US and UK aircraft have continued to violate Iranian airspace
- Iraqi television broadcasts pictures of Saddam Hussein and his younger son Qusay at what it said was a defence meeting
Coalition forces suffered the loss of a further seven servicemen - six Britons and one American - who were killed when two Royal Navy helicopters collided over international waters in the Gulf in what officials say was an accident.
Twelve died on Friday when an American helicopter crashed in the early phases of the ground operation.
Elsewhere, there are reports that four American soldiers have been killed during the coalition advance. If confirmed, this would raise the number of coalition combat fatalities to six - all of them Americans.
The BBC's Gavin Hewitt, who is with American ground forces near Nasiriya, says the Iraqi regular army there fought with more determination than anticipated.
He adds that least 200 of them eventually surrendered, while many more seem to have melted away from the fighting.
He also reports that the airfield of Tallill, which will now become a key forward operating base for coalition forces, was captured following an air strike.