The head of NATO says he remains optimistic about U.S.-European defence cooperation, particularly in missile defence, in spite of the risk of massive new U.S. budget cuts and fears of recession in Europe next year.

In an interview with Reuters, Anders Fogh Rasmussen, who often describes himself as a natural optimist, also brushed aside any concern over what impact a possible unravelling of the euro zone currency union could have on cohesion of the NATO alliance of 28 nations -- 26 of which are European.

That's a very hypothetical question, the former Danish prime minister said. I don't think it will unravel; on the contrary, I do believe European countries will find solutions to the problems in a very determined manner.

Speaking on his way back from a visit to Georgia on Thursday, Rasmussen said the economic crisis should boost his smart defence initiative to encourage greater cooperation in defence projects.

Actually, it's an old truth and very often repeated that in every crisis there is also an opportunity and I think that's what we are seeing right now, he said.

Of course, defence ministers are faced with huge challenges because of declining budgets and it's obviously a matter of concern, but it's also an opportunity to do business in new ways and in particular an opportunity to make more efficient use of scarce resources.

Rasmussen said he was confident after meeting U.S. President Barack Obama and Congressional leaders in Washington this week that NATO's flagship cooperation project -- missile defence -- would survive even if Washington were to make radically higher defence cuts on top of $450 billion (281 billion pounds) faced over the next decade.

I am sure it is ring-fenced and protected against cuts, he said. I got the impression... that there is bipartisan support for continuing that project.

He said he was also sure the Americans are aware of the importance of the U.S. military presence in Europe when it came to improving the ability of allied forces to operate together.

FEARS OF MASSIVE U.S. CUTS

The failure so far by a U.S. Congressional super committee to produce a deficit-cutting plan has raised fears of sweeping cuts in U.S. defence spending that could involve further scaling back of the U.S. military commitment to Europe.

The legislation that created the panel gave it until November 23 to come up with a plan to cut deficits by at least $1.2 trillion over the next 10 years. It will trigger automatic cuts estimated at $54.7 billion annually in both defence and non-defence spending if the committee fails to reach agreement.

Rasmussen declined to speculate on how further U.S. cuts could affect the U.S. military presence in Europe, which he called an essential element of the trans-atlantic relationship.

But obviously that military presence can adapt over time, taking into account the development in the overall security environment, he said. So we may very well see such adaptations in the wake of budget cuts, but ... at the end of the day it is a national and in this case a national American decision.

Rasmussen said he had been encouraged by recent U.S. decisions showing a strong commitment to collective defence and also an American presence in Europe.

The fact that the United States will provide an input to the NATO missile defence system demonstrates a continued American commitment to Euro-Atlantic security and the continued presence in Europe, he said.

Recently you have seen announcements that NATO allies will host such missile defence facilities. Turkey, Romania, Poland; recently also Spain. So actually you see that American presence in Europe now adapted to new security challenges and I find that quite encouraging.

The importance of the missile defence system was underlined on Tuesday when the International Atomic Energy Agency reported that Tehran appeared to have worked on designing an atomic bomb and may still be conducting secret research to that end.

Iran denies seeking a nuclear bomb and says its nuclear programme is for civilian purposes.

Rasmussen reiterated that NATO had no intention whatsoever to intervene in Iran and believed a solution should be found via political and diplomatic pressure on Tehran.

He said the missile defence programme, which U.S. officials say is to protect against attack from states like Iran, would proceed irrespective of what is going on in Iran.

The fact is that more than 30 countries in the world have missile technologies or are aspiring to get missile technologies, some of them with a range that they can hit NATO territory already.

(Reporting by David Brunnstrom; Editing by Rex Merrifield and Myra MacDonald)