Missiles slammed into palaces of President Saddam Hussein and key government buildings on Friday night in an onslaught that far exceeded strikes that launched the war on Thursday, Reuters correspondents said.

"The earth is literally shaking in Baghdad," Reuters correspondent Khaled Oweis said.

Fires broke out in the wrecked buildings. Ambulances rushed around the city, sirens wailing.

"The sky is totally lit," said Reuters correspondent Samia Nakhoul, adding that the strikes appeared to be targeting the Republican Guard and the main symbols of Saddam's rule.

"Black smoke is mushrooming into the air over the presidential palace compound," she said.

To the north, Reuters witnesses reported seeing anti-aircraft fire and explosions over the northern towns of Mosul and Kirkut.

"I can see a light patch where the city is behind a ridge. I can see anti-aircraft fire and the lights of what seem to be planes flying past," said Sebastian Alison about 25 miles from the city of Mosul.

"It's a very clear and cloudless sky."

Reuters reporter Joe Logan in Kurdish-held northern Iraq, on high ground with a view to Kirkuk, an oil city some 20 miles away in government-held territory, saw anti-aircraft fire over the city and heard several big explosions.

"I saw half a dozen bright white flashes, probably around the outskirts of Kirkuk and then heard several booms," he said. "There was a lot of anti-aircraft fire...Then there were several more flashes nearer the city and I can see smoke rising from one site near the city."

U.S.-led forces struck Baghdad with cruise missiles and bombs on Thursday in two waves, at dawn and late at night at the start of a U.S.-led strikes aimed at Saddam and other Iraqi leaders.