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International weapons inspectors have stumbled upon a new kind of bomb in Iraq that could be filled with chemical or biological agents and strewn over populated areas, Fox News has confirmed.

Baghdad also may have in its possession a drone aircraft capable of spraying harmful agents over its enemies.

Armed with this new information, U.S. officials are expected to press chief weapons inspector Hans Blix to admit he has found a "smoking gun" -- the irrefutable evidence many countries have been looking for before they agree to wage war against Baghdad -- in a closed-door session of the U.N. Security Council on Monday.

American officials hope this will help the U.S. and its allies garner more international support for military action against Iraq after March 17, the deadline proposed in an amendment to a U.S.-British resolution before the Security Council.

"It's incredible," a senior diplomat from a swing-vote Security Council nation told the London Times. "The report is going to have a clearly defined impact on the people who are wavering. It's a biggie."

The New York Times reported Monday that U.S. officials say Iraq has reconfigured rocket warheads from its stockpiles of imported or home-built weapons. Some of these makeshift weapons have been used by Iraq with both conventional and chemical warheads.

But officials told Fox News that the weapons are not rockets, but large bombs that can be dropped from wings of airplanes. Soccer-ball-sized cluster bombs then are released from the larger bombs. When triggered by a fuse, these smaller submunitions can disperse chemical or biological agents.

"We're aware" of the munition and drone discoveries, White House spokesman Ari Fleischer said Monday.

"It's a matter of no small concern because of how dangerous these weapons can be and the fact that they can carry chemical and biological [agents]," he added.

This all could make life much more difficult for Saddam, who, in the past few days, has been trying to prove to the world that he is cooperating with weapons inspectors to prove he has no banned weapons.

Iraq still insists that it has destroyed all of its old chemical warheads, a claim the inspectors have not verified.

Senior U.S. officials confirmed to Fox News on Monday that the inspectors initially found just one of these munitions, then another, and eventually uncovered the manufacturing capability.

Submunitions -- designed to be expelled as a bomber nears its target -- are rubber covered so that when they hit the ground, they bounce up. This increases the blast radius, which is why they are used for high explosives.

But Baghdad's submunitions aren't rubber covered.

Though Iraq claims the weapon is used for high explosives, the munitions have holes bored into them. These holes are usually used to inject chemical or biological weapons into the warhead, making these types of submunitions an ideal carrier.

U.S. officials say the Iraqis apparently have hundreds of these weapons, which were discovered sometime within the past several months.

Iraq claimed these cluster munitions were used as high explosives and were supposed to bounce. It said the rocket was designed as a conventional cluster bomb, which would scatter explosive submunitions over its target, and not as a chemical weapon.

But the United States didn't buy that argument, and the Iraqis have now admitted that some might have been configured as chemical weapons.

"If you take the kinds of fuses we know they have, and you screw them in there, when these things come out from the main frame and they explode inward, chemical agents come out," one U.S. official told the Times. "These can be used for biological weapons, too."

U.S. officials are expected to argue that this is just one more nail in Iraq's coffin, especially in light of a 167-page report handed out to the U.N. Security Council by Blix on Friday. The report details Iraq's 12-year history of deception when it comes to weapons inspections.

The United States and Britain are hoping this part of Iraq's "catalog of deception" -- as Secretary of State Colin Powell called it last week - will help win over some countries who thus far have been fence-sitters on a U.S.-backed resolution authorizing the use of force in Iraq.

Powell said Sunday that Blix should have made more of the evidence in that report when he appeared before the Security Council last week.

"When you look at page after page of what the Iraqis have done over the years to hide, to deceive, to cheat, to keep information away from the inspectors, to change facts to fit the latest issue, and once they put that set of facts before you, when you find you those facts are false, they come up with a new set of facts -- it's a constant pattern," Powell said on Fox News Sunday.

He hinted that the United States would release more information about prohibited weapons as the council debates a resolution this week.

"That's the kind of thing we're going to be making some news about in the course of the week and point this out," he said. "And there are other things that have been found that I think more can be made of."

Another piece of information that supports the U.S. position is the discovery of a secret drone in Iraq, the London Times reported on Monday.

Fox News has learned that this drone is probably larger than the one mentioned by Powell in his intelligence briefing of the council on Feb. 5.

During that briefing, Powell said the United States had watched an unmanned Iraqi aircraft be test-flown for 310 miles non-stop in a racetrack pattern. He said then that Iraqi drones, fitted with spraying devices, could produce a chemical or biological attack not only on Iraq’s neighbors but also, if transported, on the United States.

U.N. sources told the London Times that the latest drone was found by a team led by a British weapons inspector and wasn't mentioned in Blix's oral presentation Friday because more information was being sought. A reference to the drone was included in the 167-page report Blix submitted.

"I think he could have said a lot more about Iraqi non-compliance," Powell said.

Fox News' Jim Angle, Todd Connor and James Rosen contributed to this report.