The aerial bombardment accompanied increased ground fire on Falluja in a bid to turn up the heat on the anti-American forces the US believes are holed up inside.
"First Marine Expeditionary Force conducted coordinated offensive operations in and around the Falluja-Ramadi area," the military said in a statement on Saturday, without specifying where the strikes occurred.
It "destroyed three barricaded fighting positions, an anti-aircraft weapon and a weapons cache".
The latest wave of four air raids, in support of ground troops, began at 3.30am (0030 GMT) on Friday and finished at 12.20am on Saturday.
More than 1000 US and Iraqi troops have gathered around the fringes of Falluja, 50km west of Baghdad, since mid-October, while the US military is doubling its manpower in Ramadi to 2000 amid expectations of a two-pronged show-down to crush Iraq's nerve centres of anti-US action.
On Friday, interim Prime Minister Iyad Allawi said in Brussels that the chance for a peaceful resolution to the stand-off was dimming.
Many of Falluja's 300,000 inhabitants are thought to have already fled to makeshift camps to the west or sought refuge in Baghdad, while US planes have been dropping leaflets urging those few remaining to leave.
All roads in and out of the city have been closed except for possibly one rural road through the towns of Khan Dhari and Amiryat al-Falluja west of the Iraqi capital, which was last reported to be open on Thursday.
Many of Falluja's 300,000 citizens
are thought to have fled
A government-backed delegation of four members of the interim parliament has been negotiating with leaders from Falluja, but hopes for a peaceful settlement are fading fast.
"The encircling of the city has increased. Things are getting worse," said one member of the negotiating team from the national council.
Despite the desperate need for talks, the Falluja officials, who first went to Baghdad on 27 October in the latest round of discussions, had not been in touch for three days, the mediator said.
"We are trying to get in touch. We'll try again," he said, speaking on condition of anonymity.
Earlier discussions between Baghdad and Falluja delegates collapsed in mid-October after Allawi threatened them with invasion if they did not surrender Abu Musab al-Zarqawi and other suspected Muslim fighters believed to be using the city as an operating base.
City leaders insist that the Jordanian-born al-Zarqawi, wanted for a string of deadly attacks and beheading of captives, does not reside there.
Iyad Allawi says chances of a
peaceful resolution are dimming
In a sign of an intensified effort to crush pockets of resistance before national elections promised by January, US marines south of Baghdad, with help from Iraq's fledgling security forces, claimed to have captured 41 suspected anti-US forces in a series of raids.
'Captured or killed'
The American troops "are going to make the terrorists taste defeat. The more bitter, the better", declared Colonel Ron Johnson in a separate statement.
The fighters "will be captured or they will be killed. Either way, they will be ushered off the Iraqi stage".
The Friday raids took place in northern Babil, which spans through Mahmudiya, Latifiya and Iskandariya - the "triangle of death" - and is believed to have strong ties to Falluja and Ramadi to the west.
A British battle group arrived in the region late last month from the relative calm of southern Iraq to free up US troops for the expected Falluja assault.