The launch was delayed last week after Canada expressed concern that rocket debris could fall on the oil installations off Newfoundland, prompting authorities to evacuate workers from the platforms.

Titan IV, which will carry a military satellite into orbit, will take off in a few days from Cape Canaveral, Florida.

"The US Air Force would be able and prepared to destroy the rocket in the unlikely event that unforeseen circumstances arise that could result in the rocket booster falling outside of the identified safety zone," said Newfoundland Premier Danny Williams.

Williams said the assurance was given to him by Canadian Deputy Prime Minister Anne McLellan, who had been in contact with US authorities.