But, McCallum added, Canada had not yet signed on to the US system.

He said negotiations would be held with Washington and, once completed, the plan would be presented to the cabinet for final approval.

Addressing the House of Commons, McCallum said: "The government has decided to enter into discussions with the United States on Canadian participation in a ballistic missile defense system."

However, he emphasized "our participation is not unconditional." It would depend, he said, on "our national interests."

Nevertheless, McCallum strongly indicated that it is the intention of Ottawa to join the US in the missile defense system.

"If we are not inside the tent, our ability to influence the Americans will be zero," he said.

"One thing is sure: If we are not part of this we will have no influence."

McCallum, in an apparent effort to deflect criticism of the missile defense system from inside his own governing Liberal Party, rejected charges the US system was just a scaled-down version of an old US proposal for a space-based missile defence system.

He insisted on "Canada's continued opposition to the weaponization of outer space."

As far as the Canada-US negotiations were concerned, McCallum said it made sense to have the new missile defense system under the umbrella and command of the already-existing binational North American air defense system, known as

US officials have said that if Canada joins the new missile defense system, it would probably come under the command of NORAD, which is based in Colorado Springs and has a Canadian officer as its permanent deputy commander.

The US officials also have said that if Canada stays out of the new system, it would probably come under the control of the US Northern Command.

WAR.WIRE