When it comes to a missile defense system, there has always been a conflict between NATO and Russia. How do you see NATO's ties to Russia today?

There is a clear link between what we say and what we do. When we met in Lisbon, we had the NATO-Russia summit, and we decided to develop a true strategic partnership between NATO and Russia. We want to pursue that. In that context, we invited Russia to cooperate on missile defense and that invitation still stands. We have made clear from the outset that NATO has made the decision to establish a NATO missile defense system, because it is our obligation to ensure effective defense of our populations, and we consider the missile threat a real treat and against that we need a real defense. That is the essence of being a defense alliance.

The positive news is that during the last three years, we have moved forward in the NATO-Russia cooperation when it comes to practical cooperation on Afghanistan, counter-terrorism, counter-narcotics, counter-piracy. I think we have achieved progress in our relationship.

What is your view of the defensive abilities of NATO looking at the fact that the United States is looking to take a more of a cautious international role?

We will see a continued strong partnership, and we will also see the United States continue to contribute to joint operations, but you will see a change in the US engagement in Europe. A change that reflects the change of security challenges. You will see a drawdown of stationary forces as we knew them during the Cold War. But things have changed, and we are now faced with new security challenges.

The large US contribution to a NATO missile defense system is an example where the United States renews her engagement in European security, but now with a focus on an emerging security challenge. Another example, the US has also decided to rotate military units to participate in the NATO response force and that contributes to stepping up our training and exercise activities in the future.

As we draw down our operational tempo, we will step up our endeavors within training and exercise to maintain and further develop our capability to operate together. There are examples of a new kind of US engagement in European security, and I welcome that.

Islamic terror is currently advancing in Africa. The most recent example is in Mali. What does that mean for NATO?

The UN Security Council has adopted a resolution, according to which an African-led stabilization force should take action in Mali. This is the reason why I don't see a role for NATO. Having said that, I welcome that France, a NATO ally, has taken swift and very effective action because it was high time to stop the terrorist groups from further advancing into Mali - and also to pave the way for this African-led stabilization force. And I welcome that individual NATO allies have decided to support this very important French-led mission.

We have partnerships with countries in North Africa and the Middle East and, within the framework of these partnerships, we can provide assistance when it comes to reforms and modernization of the security sector, for example. Countries in transition toward democracy will also experience how important it is to put the security sector under democratic control and upon request we can assist our partners in that respect.

There is still no clear plan for what comes after Western troops withdraw their troops from Afghanistan. Does that not breed uncertainty?

I think a growing awareness of how important it is to devote a sufficient amount of resources for investment in critical military capabilities. We have learned lessons from our operation in Afghanistan as well as Libya and Mali. Actually, Mali is not a NATO operation, but NATO allies operate in Mali. And what we see is that the positive side - European-lead as we have seen in Libya and Mali - should be seen in the context that such operations could not be carried out without a significant American contribution.

I think European allies realize that it is necessary for Europe to invest more in long-distance airlift capacity in air-to-air refueling as we learned in Libya, in reconnaissance capabilities. In all these areas we need more investment and that is my plea. Resources that are freed up as we draw down our operations tempo could be reinvested in such much-needed military capabilities because they will be needed in the future.

Anders Fogh Rasmussen has been NATO's secretary-general since 2009.