WASHINGTON (REUTERS) — NATO surveillance planes start patrols of U.S. skies on Friday to help avert further attacks like those on New York and Washington a month ago, a senior State Department official said.

“Five have deployed in the United States. They’ll be operational as of tomorrow,” the official told reporters on Thursday, speaking on condition of anonymity.

The NATO alliance has 24 Airborne Warning and Control Systems Aircraft (AWACS) based at Geilenkirchen near Germany’s border with Belgium, and at a base in Waddington, Britain, the Supreme Headquarters Allied Powers Europe says.

“They will provide air defense for the United States, and that adds to this sense that Europe is coming to the defense, literally coming to the defense, of the United States,” the official said.

He noted the irony that NATO’s founding treaty 52 years ago had in mind Washington coming to Europe’s defense with its clause allowing for collective security efforts, if one member state came under foreign attack.

The decision, after talks between NATO Secretary-General George Robertson and U.S. Ambassador Nick Burns, to invoke the clause for the first time by declaring the Sept. 11 assaults an attack on the whole alliance, turned that expectation on its head, he said.

“There was no flinching on Sept. 12 when we presented this to the North Atlantic Council,” the official said, referring to NATO’s decision-making body.

“Everyone agreed to this in six hours, which was the equivalent of a nanosecond, the way NATO works,” he added.

Alliance countries shared the shock of the United States at the huge loss of life when hijackers crashed planes into the World Trade Center in New York, the Pentagon outside Washington and the countryside near Pittsburgh, killing more than 5,400 people.

Following the decision to invoke the clause, Article Five, Washington submitted a list of requests to the alliance, which made air space, ports and standing naval fleets available to the U.S. campaign against Afghanistan, where the prime suspect, Osama bin Laden, is believed to be based.

“The European population feels a shared sense of vulnerability with the American population. I think it is well understood that if there can be attacks in New York and Washington, there may well be attacks in Europe itself,” the official said.

MORE THAN JUST SYMBOLIC

He denied the deployment of the AWACS planes was purely symbolic and that Washington could defend its skies alone.

“We have been attacked on our soil. We need air defense in the continental United States, from Alaska to Hawaii,” he said.

“We have finite assets. We have deployed a number of assets to the theater. We now need air defense in the United States, and NATO has stepped forward to provide that, so it’s not just symbolic,” he said.

He added, “There is huge symbolic importance in what has happened with Europe coming to our defense through NATO aircraft, but it has a very practical and concrete benefit to the United States.”

Perhaps most symbolic of all is the participation of German troops in an effort to protect U.S. territory as part of an alliance created four years after the end of World War Two.

About 50 of the 200 NATO soldiers who will accompany the planes to boost a U.S. effort to patrol the skies are German, a NATO official said.