US President George W. Bush on Wednesday envisaged an "unprecedented level" of cooperation between Russia and NATO by integrating former Soviet military sites into an anti-missile system in Europe.

"We are inviting Russia to join us in this cooperative effort," said Bush in Bucharest, venue of a NATO summit that will also include Russian leader Vladimir Putin.

He proposed that Soviet-era military sites could be part of a "threat-monitoring system," and added: "This could lead to an unprecedented level of strategic cooperation between Russia and the NATO alliance."

Bush's remarks were seen as referring to a proposal by Putin to make a radar installation in Azerbaijan — a former Soviet republic — part of a next-generation missile defence shield.

The United States argues that missile defence is urgently needed to thwart a possible threat from Iran, which is suspected in the West of developing nuclear weapons — a goal that Tehran denies.

With its growing oil wealth and resurgent power, however, Russia suspects that it could be the actual target of the missle shield.

Bush argued that Iranian missiles had the range to hit Israel and Turkey today, and might at some point in the future be able to hit the United States or all of Europe.

He said he would tell Putin in Bucharest "that the missile defense capabilities we are developing are not designed to defend against Russia just as the new NATO we are building is not designed to defend against Russia".

"The Cold War is over," the president added. "Russia is not our enemy. We are working toward a new security relationship with Russia whose foundation does not rest on the prospect of mutual annihilation."