The United States and Britain appeared to have scored the first significant victory in their war to topple the regime of President Saddam Hussein when they invaded southern Iraq last night and captured the port of Umm Qasr.
The capture, reported by the Kuwaiti News Agency, was denied by Iraq. The border town is Iraq's main seaport, located north of Kuwait's Bubiyan island and west of the Shatt el-Arab waterway. It was the only entry point for direct port deliveries into Iraq.
The invasion, of land forces sweeping over the Iraq/Kuwait border and an amphibious assault directly into the port by Royal Marine Commandos, took place as Baghdad was subjected to renewed aerial bombardment by cruise missiles and laser-guided precision bombs.
The US Defence Secretary, Mr Donald Rumsfeld, earlier warned the regime that it faced an assault, the scale of which was "beyond what has been seen before".
Within hours, coalition forces set out to prove him correct. In Baghdad, government buildings in the centre of the city were burning heavily after renewed bombing.
An annex to the defence ministry adjacent to President Saddam's main presidential compound was in flames and two other buildings in the city centre were also on fire. One of the targets struck was an office of Deputy Prime Minister Tareq Aziz.
The bombardment was heavier and more sustained than the attack announcing the start of the war in the early hours of yesterday. The sky filled with smoke, and residents feared that the Pentagon's threat of "shock and awe" was about to be fulfilled.
The massive land invasion from Kuwait followed an hour-long artillery battle between Iraqi and coalition forces. Hundreds of shells were exchanged before an aerial bombardment of Iraqi positions over the border, including the southern city of Basra - the coalition's initial target.
During the artillery duel, the air was thick with the sound of overhead traffic and of falling bombs detonating. A squadron of Cobra attack helicopters could be seen flying towards the border to engage with the Iraqi artillery pieces.
US special forces are also reported to have engaged in a heavy gun battle near the border town of Safwan, overlooked by Safwan hill where many of the Iraqi artillery pieces appear to have been based, guarding the road to Basra.
But despite the airstrike sporadic Iraqi shelling continued, with mortar rounds landing in and around allied positions.
"There's pandemonium out here. I'm not sure this was part of the plan," one British officer said. "Iraqi forces appear to have been deployed in different positions to those reported by our surveillance reports. Its going to take us some time to readjust."
Prior to the invasion, Iraq responded to the first phase of the war by firing several missiles at Kuwait. One was believed to have been intercepted by US Patriot anti-missile batteries but one got through. It exploded but injured no one.
The attack, however, caused Kuwaitis to flee into bunkers and don gas masks. Coalition troops also donned protective clothing and masks.
Through the day, there were repeated air raid warnings in the emirate but no further attacks.
Despite the significant escalation of the war, US officials said the invasion and renewed bombings did not represent the massive military "shock and awe" attack predicted by Mr Rumsfeld.
"This is all part of the preparation" for a major ground attack, one said. "There will be things that you see and things that you don't."
In an attempt to counter world-wide criticism for attacking Iraq without UN backing, President Bush claimed to have the support of a growing number of nations.
In a brief White House appearance Mr Bush said that more than 40 nations now supported the US "in the ever-growing coalition of the willing, nations which support our great desire for peace and freedom".
In 1991 a total of 38 countries gave material or logistical support to the coalition assembled by President Bush's father.
US Secretary of State Colin Powell said three days ago that 45 countries supported the US but that 15 "for one reason or another do not yet wish to be publicly named".
Ireland is believed to be among the 15.