NEW YORK, May 19: US Vice President Dick Cheney said on Sunday that the chance of more Al Qaeda attacks against US targets was “almost a certainty” and urged Americans to stay vigilant.

“I think that the prospects of a future attack on the US are almost a certainty,” Cheney told NBC’s Meet The Press talk show. “It could happen tomorrow, it could happen next week, it could happen next year, but they will keep trying. And we have to be prepared.”

He also said the United States could not have anticipated that terrorists would turn four commercial airliners into missiles on Sept 11, responding to criticism the Bush administration ignored warning signs about those attacks.

US officials do not know when the attacks might occur or what the targets might be, Cheney said.

Observers said US officials were this spring once again evaluating a growing body of intelligence suggesting that another large scale Al Qaeda attack may on Europe, Middle East or the Middle East may be in the planning stages.

Asked if Osama bin Laden’s network was planning to strike American targets, Cheney said on Fox News Sunday: “We assume they are. There is certainly a level of noise out there in the system that would indicate that those efforts are continuing.”

The suggestion is that the network is reconstituting itself after a winter of disruptions caused by US military operations in Afghanistan and widespread arrests across the globe.

He advised Americans to stay alert, watch for anything out of the ordinary and go about their lives.

“We’ve got to do that. We can’t shut down the country because of the possibility of another attack,” Cheney said.

“The terrorists win if they shut down our country and don’t even attack; just simply do it based on the threat.