BRITISH and American forces rained thunder on the heart of Baghdad last night in a blitzkrieg designed to terrify Iraqi leaders and their Republican Guard into surrender.

Wave upon wave of bombs and missiles triggered deafening explosions and giant fireballs that left buildings ablaze and sent towering plumes of red, pink and thick brown smoke into the sky.

The relentless onslaught of a thousand cruise missiles and a thousand airstrikes was precisely aimed at President Saddam Hussein’s political and military power base. Fires raged at his palace complexes and key government buildings as tracer fire from anti-aircraft batteries arced overhead. Several hundred military targets around the country were also attacked.

The strategy appeared to pay immediate dividends when an entire division of some 8,000 men was reported to have surrendered to US Marines advancing towards Basra, Iraq’s second city. The 51st Division, whose task was to protect the key oil shipment hub, was one of Iraq’s better equipped forces, with about 200 tanks before the war.

The bombing of Iraq was intensified after American officials revealed that special forces had been negotiating with Republican Guard leaders. The awesome display of firepower was designed as much to increase the pressure on them to surrender as to destroy targets vital to Saddam.

Announcing the start of the air war, Donald Rumsfeld, the US Defence Secretary, said the goal was to strike “with force on a scope and scale that makes clear to Iraqis that he (Saddam) and his regime are finished. With the start of the air war it may be that we find people responding.”

Surrender talks between coalition forces and Iraqi chiefs have gathered pace in recent days, and a senior American official said yesterday that General Tommy Franks, the US commander in the Gulf, would scale the intensity of the bombardment in accordance with progress in those talks. If they did not reach a successful conclusion, the bombing would go “full-throttle”.

Military intelligence chiefs have stepped up their e-mail and mobile phone contacts with generals about laying down their arms, and these conversations encouraged American officials to believe that Saddam was losing his grip on power. That view was supported by an intelligence assessment that communications between Iraqi leaders had fallen sharply in the past 48 hours. “Saddam’s inner circle is starting to collapse,” one official told The Times.

The American claims were impossible to verify, and may simply be part of the intense psychological campaign being waged by CIA and US military chiefs to sway Iraqi generals. But despite their optimism, negotiations had not produced defections on the hoped-for scale although — besides the men, from the 51st Division — hundreds of Iraqi soldiers have surrendered and US Marines in the south of Iraq said they were holding more than 600 prisoners.

It was the promise of a mass surrender without a bloody street battle for Baghdad that persuaded General Franks to soften his opening salvo, and for the first two days of the war America notably did not use its new “microwave” bomb, which destroys electronic connections and would have disrupted e-mail communications.

Yesterday, however, the threatened “shock and awe” bombardment began, with the departure of B52 bombers from RAF Fairford in Gloucestershire. Massive explosions rocked not only Baghdad and its suburbs, but also Kirkuk, Mosul and Saddam’s home town of Tikrit.

In the first three-hour assault, American warships fired 320 cruise missiles at Baghdad and its suburbs — more than were fired in the whole of the first Gulf War and three times as many as were launched in the previous two days. General Richard Myers, Chairman of the Joint Chiefs of Staff, said that “several hundred military targets” would be hit, and American forces returned to strike at Baghdad again and again through the night. As dawn broke, yet more missiles caused huge explosions in the centre of the city.

The bombardment was precisely targeted on Saddam’s five-mile-long presidential complex along the banks of the Tigris and while its buildings blazed, neighbouring tower blocks stood untouched, their power supply unaffected, the street lights still on.

During the initial attack, however, a rocket hit an Iranian oilfield depot at Abadan, injuring two people. Iranian officials said that it was a bomb from an American plane.

Early today the Pentagon announced that 1,000 cruise missiles had been launched and 2,000 sorties flown, including 1,000 bombing missions. The blitz involved about 100 bombers, including almost every British Tornado GR4. “This is one of the big nights of the air battle,” a military source said.

Returning pilots reported that they had encountered intense anti-aircraft fire as they approached Baghdad. “There were explosions all around us,” one said. “The first night is always the toughest. It will get a little easier from now on because of the targets we eliminated tonight.”

Mr Rumsfeld had earlier given clues about the extent of the unseen war being waged for the loyalty of Iraqi generals. “There are communications in every conceivable mode and method, public and private, to the Iraqi forces, that they can act with honour and turn over their weapons and walk away from them, and they will not be hurt,” he said.

US planes have dropped more than two million propaganda leaflets a day in recent days, bringing to 20 million the number dropped over Iraqi military units in recent weeks.

One official said: “It seems the faith in Saddam is starting to wane. We are getting more and more reports that Iraqi commanders are telling their units to stay in their barracks and wait for the Americans to arrive so they can surrender.”

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