US Marines claim to have seized a key bridge over the Tigris river in central Iraq and have taken control of the main highway from Kut to Baghdad, media reports said Wednesday. "That's the last big bridge we needed" for an advance on Baghdad, a senior Marine officer told a Reuters correspondent near Kut.

A US army officer said today's action is a major move. But, added, there are still tank battles continuing.

The officer said the Marines are in control of the main highway on the north bank of the Tigris from Kut to Baghdad. U.S. troops have approached to within 80 kms of Baghdad from the south.

Meanwhile, U.S. warplanes pounded Baghdad on Wednesday, striking a presidential compound where President Saddam Hussein's son Qusay has his headquarters. After a lull in bombing for most of the night, strikes resumed shortly after 3 a.m. Republican Guards are believed to have dug in south of the city to defend the regime from advancing U.S. troops.

Anti-aircraft fire was also heard on the outskirts. The air assault in and around Baghdad appeared to target command, communications and military facilities. Three bombs hit the compound near the Tigris River where Qusay Hussein, who commands the Republican Guard, is based. The compound has been struck several times before in recent days.

PHOTO CAPTION A car burns on a bridge over the Euphrates River, which the U.S. Army seized in Al Hindiyah, Iraq Monday, March 31, 2003. (AP Photo/John Moore) March 31 11:10 AM ET