The U.S. military was apparently poised to launch a blistering aerial bombardment on Baghdad on Friday while U.S.-led coalition forces advanced deep into Iraq, seizing crucial oil installations, airfields, a deep-water port and a southern peninsula.

The CNN television network said a massive U.S. air bombardment on the Iraqi capital was expected Friday night in what Pentagon officials describe as ''A-Day,'' a ''shock and awe'' campaign designed to shock the Iraqi military into surrender.

For the third night in a row, warning sirens went off in Baghdad Friday night and antiaircraft fire heard on TV images broadcast by CNN and explosions were reported heard in the Iraqi capital.

In Washington, President George W. Bush on Friday briefed Congressional leaders of U.S. war effort and said the military campaign is ''making progress'' and he was determined to press ahead with the avowed U.S. objective to rid Iraq of weapons of mass destruction and remove Iraqi President Saddam Hussein from power.

''We will stay on task until we achieve our objective,'' Bush told reporters.

At the State Department, U.S. Secretary of State Colin Powell laid out the possibility of speeding up the military campaign, urging Iraqi leaders to abandon the Saddam regime.

''To prevent any loss of life beyond that which may have occurred already, it would be wise for Iraqi leaders to recognize that their days are over,'' Powell told reporters, noting that the message was being conveyed to Baghdad through individuals and countries around the world.

On the war front, BBC News reported that U.S. Marines reached Iraq's only deep-water port at Umm Qasr in the country's southeast after overcoming early resistance as they crossed the border from Kuwait.

But despite reports of about 250 Iraqis surrendering in the area, the report said the Marines have not yet gained control of the whole complex.

CNN, quoting a senior U.S. military official, reported that U.S. and British troops seized two strategically important airfields in western Iraq and are in control strategic oil fields in southern Iraq.

The two western Iraq airfields, known as H-2 and H-3, are considered important to the continued military operation inside Iraq, the report said.

Britain's Defense Ministry said British troops have secured the Faw Peninsula, Iraq's only Persian Gulf coast located at the country's southern tip. British troops say they have taken control of key oil installations on the nearby al-Faw peninsula.

The BBC reported that Australian special forces -- part of a 2,000-strong contingent sent to the Gulf -- are operating deep inside Iraq, identifying troops movements and military targets.

The British news agency Press Association quoted a spokesman for British forces in the Persian Gulf as saying Friday that U.S. and British forces may enter Baghdad within ''three or four days.''

In Baghdad, Iraqi Information Minister Mohammed Sa'eed al-Sahhaf said Friday that Saddam survived the U.S. air strikes on his residence and family, but U.S. intelligence sources are still trying to determine the leader's fate.

According to the state-run Iraqi News Agency on Friday, Saddam has issued a presidential decree promising Iraqi troops huge awards as incentives to shoot down enemy planes and capture enemy soldiers.

The decree promises 100 million dinars, ($40,000) for shooting a jet fighter, 50 million dinars for shooting down a helicopter or capturing an enemy solider and 25 million dinars for killing an enemy soldier, the agency said.

Two U.S. Marines were killed in action Friday in southern Iraq, becoming the first coalition combat casualties of the war, CNN said, quoting U.S. Marines in Kuwait.

The fatalities came hours after a U.S. Marine helicopter with U.S. and British forces on board crashed near the Iraq-Kuwait border. Eight British and four U.S. troops were killed in the crash, Pentagon officials said. There were no indications that hostile fire brought down the helicopter, according to the Pentagon.

In Washington, an opinion poll shows Bush's approval rate rose sharply after he ordered U.S. armed forces into war on Wednesday, shooting up to 67% from around 50% in previous surveys.

The survey, conducted by the Washington Post and the ABC network on Thursday, also shows 72% of the Americans support the war.