U.S. warplanes launching from the Gulf are pounding Republican Guard positions south of Baghdad to soften defenses around the Iraqi capital in preparation for a U.S.-led ground assault, senior Navy officers said.

Navy strike planes took off Saturday from the USS Kitty Hawk for the latest bombing missions to support Army and Marine forces consolidating south of Baghdad.

The two other U.S. carriers in the Gulf, the USS Constellation and the USS Abraham Lincoln, are conducting similar operations. Scores of flights were scheduled for later Saturday and into Sunday morning.

The bulk of close to 100 bombing missions a day from each carrier have been at night and have hit artillery, command posts and vehicle convoys of the Republican Guard's Medina division and other targets.

Rear Adm. Barry Costello, the commander of the Constellation battle group, told reporters Saturday morning that planes from his ship hit 40 targets in the past 24 hours.

They included a Republican Guard headquarters near Kut and artillery and personnel carriers in the same region, in support of nearby Marines. Other targets were buildings, vehicles and fuel trucks north of Hillah, in support of the Army's V Corps, he said.

"These are all close air support missions in order to prep the battlefield for the advance of our ground troops," Costello said.

Kitty Hawk-based planes dropped 46 bombs on missions into the early hours of Saturday, including six 2,000-pound target penetrator, or "bunker buster" satellite-guided bombs, eight JSOW satellite-guided bombs, 26 500-pound laser-guided bombs and six 500-pound unguided bombs.

Kitty Hawk-based planes hit a Baath Party headquarters, surface-to-surface missile canisters, a military compound, other buildings, tanks and an early warning radar site, officials said. All the targets were between Karbala and Baghdad.

The three carriers in the Gulf have flown around 1,400 sorties since the war started, Capt. Dick Corpus, the Kitty Hawk's chief of staff, said Friday. He didn't provide details of the number of bombs dropped.