The aircraft, at high altitude, made three consecutive overflights about 15 minutes apart.

Around the same time, bombing was clearly heard in the city centre from the southern rim where artillery blasts had resumed mid-morning.

US fighter aircraft began Saturday flying 24-hours a day over Baghdad to protect ground troops fighting their way into the capital, a US general said.

On Sunday, the city appeared relatively normal, with slow traffic and public transportation running as usual.

Most shops were still closed, but cafes opened for early morning risers drinking the traditional dark tea in small groups on the sidewalks.

On the al-Kharkh western bank of the Tigris river, which cuts Baghdad in two, activity seemed more reduced than on the al-Rusafa bank.

Al-Kharkh is home to the US-controlled airport, a number of Saddam Hussein's presidential palaces and key ministries which have been the main targets of coalition missile strikes.

The Iraqi capital had come under renewed coalition bombardment just before dawn Sunday.

Beginning around 5:00 am (0100 GMT), explosions and artillery fire could be heard coming from the south as well as occasional blasts in the city center.

At least two massive explosions were heard in central Baghdad just after midnight (2000 GMT Saturday), another AFP correspondent had reported.

The exact targets of the explosions were unclear, but the correspondent said the blasts were unusually powerful. Explosions were still heard half an hour later.

On Saturday night, a missile struck the Tigris river next to Saddam Hussein's main presidential palace about the same time a plane roared overhead. Smoke rose briefly from the water.

The sprawling Republican Palace on the banks of the Tigris has been repeatedly hit by bombs or missiles since the US-led coalition launched the war to oust Saddam on March 20.

The overnight activity came after US troops rode tanks deep into Baghdad for the first time in a bid to show the Iraqi people that Saddam no longer wields absolute power.

They met resistance and a small area of southwestern Baghdad became a battlefield with abandoned Iraqi military vehicles burning on the streets.

SPACE.WIRE