Missiles and bombs rained o­n Baghdad and two other Iraqi cities as the United States unleashed what it called its 'shock and awe' strategy this morning.

A Reuters report said the aerial assault triggered giant fireballs and deafening explosions above the capital city. US warplanes also assailed targets in the northern cities of Mosul and Kirkuk.

US officials hoped that the 'A-Day' - a reference to the massive air campaign - would convince the Iraqi leadership to surrender.

Defense Secretary Donald Rumsfeld told a news conference that the assault was intended to show Iraqis that their president, Saddam Hussein, was finished and his rule "history."

"The regime is starting to lose control of their country," he told reporters at the Pentagon.

According to BBC , the targets in Baghdad included Saddam's palaces while the Foreign Ministry and the deputy prime minister's office were also ablaze.

Despite the heavy bombardment, Iraq's Defence Minister Sultan Hashim Ahmed told a news conference later that "no force in the world" would conquer Iraq.

1,500 bombs and missiles

Meanwhile, CNN reported that US forces plan to drop more than 1,500 bombs and missiles across Iraq in the first 24 hours of its "shock and awe" campaign.

US officials said o­ne of the weapons being used was a new 5,200 kg bomb designed to limit collateral damage for optimal use in an urban environment.

The report quoted chairperson of the Joint Chief of Staff Gen. Richard Myers as saying that coalition warplanes had flown more than 1,000 sorties and have "dropped scores of precision-guided munitions" o­n Iraqi military targets so far.

Iraqi Information Minister Muhammad Saeed al-Sahaf said the capital city's Peace Palace, which is used to house visiting dignitaries, and the Flowers Palace, a museum that o­nce was a palace for the king during the days of royal rule, were also damaged in the raid.

Also severely damaged was the mammoth Republican Palace along the Tigris river.

This prompted the minister to label the US-led coalition forces as "mercenaries". Last night, Muhammad Saeed had called President George W Bush as the "leader of the international criminal gang of bastards."

'Chemical Ali'

In a related development, ABCNews reported that three key Iraqi officials were killed in what the Pentagon termed as 'decapitation' strikes two days ago.

The trio were Taha Yasin Ramadan, Izatt Ibrahaim al Douri, and Ali Hassan Majid known as 'Chemical Ali'.

Ali Hassan earned his chilling nickname by using chemical weapons to suppress a Kurdish rebellion in Northern Iraq in 1987 and 1988. Hundreds of villages were razed, and more than 100,000 Kurds died.

Another Reuters report said that US warships had fired as many as 320 Tomahawk cruise missiles to strike military targets around Baghdad today.

The commander of the Kitty Hawk battle group Rear Admiral Matthew Moffit told reporters the missiles were launched from warships in the Red Sea and Gulf, and were coordinated to hit their targets almost simultaneously.

"The intention is to convince the (Iraqi) regime that it's time to leave and, if they don't, we're going to take them out," he said.

Carrier-based warplanes from the USS Kitty Hawk and USS Constellation were also involved in stepped-up bombing runs o­n Iraqi targets as.

Commander of the Kitty Hawk's air wing Patrick Driscoll said F-14 Tomcat and F/A-18 Hornet strike fighter aircraft were dropping satellite- and laser-guided bombs in support of the Army's Fifth Corps around Nassiriya and other areas in southeast Iraq.

He added that Kitty Hawk-based warplanes were also bombing in support of U.S. Marines in the Basra area.