NATO head Anders Fogh Rasmussen hopes EU leaders will commit to new military capabilities and cooperation at this week's summit, with a strong Europe in everyone's interest.
"We need a Europe that is committed to security, we need a Europe that is outward looking and taking on a global perspective," Rasmussen told AFP in an interview.
The 28 European Union leaders meet Thursday and Friday in the first summit dedicated to defence since 2008, trying to balance tight budgets against the ever rising cost of military hardware.
It is expected they will agree to invest in drones and air-to-air refuelling, key assets which the NATO-led Libya campaign of 2011 showed were lacking in Europe's arsenal and forced it to rely on the United States at key points in the conflict.
"We need a stronger Europe -- a stronger Europe also means a stronger NATO," Rasmussen said.
The economic crisis, he conceded, was a major concern but it was also an opportunity to promote cooperation, the 'pooling and sharing' meant to ease the defence burden.
"It will be increasingly difficult for European nations to purchase advanced expensive military equipment in the future on their own," he said.
"If they pool and share resources, if they go for joint efforts ... if we do it together, then we can acquire these military capabilities," secretary general Rasmussen said.
Duplication is a waste.
"We need complementarity ... for instance, if European nations give priority to developing an air-to-air refuelling capacity there is no reason for NATO to do the same," he said.
Former Danish premier Rasmussen has headed the 28-member NATO since 2009 and steps down in September next year after it holds a summit in Britain devoted to boosting such cooperation to cope with the challenges ahead.
Russia, ties with former Soviet states
Some 22 EU members, led by Britain and France, play an important role in NATO, which the US set up to rally its European allies against the Soviet Union in the Cold War.
Relations with Russia still prove difficult today, with NATO's and the EU's policy of drawing in former Soviet states such as Ukraine bitterly opposed in Moscow.
Rasmussen insisted Russia had no reason to fear such developments.
While "obviously we do not agree with the Russians on all issues," he said, "in other areas we have developed a well functioning practical cooperation."
Just as for NATO and the EU, "it is also in Russia's interest to have security and stability along its western borders."
"NATO and the EU have provided that security and stability ... I know that the Russians do not necessarily agree with me on that assessment but (it) is my firm conviction that at the end of the day, this is also in Russia's interest."
Asked about the possible impact on NATO of Washington's "pivot' towards Asia, Rasmussen said he saw no reason for this to cause concern or cast doubt on the US commitment to Europe.
"First of all I think it is also in Europe's interest that the US engage more actively in the Asia-Pacific region, taking into account the rise of emerging powers like China," he said.
"I do not see that pivot to Asia taking place at the expense of the transatlantic relationship."
At the same time, Rasmussen said he thought it was legitimate that Washington asks its NATO allies to foot more of the bill.
"Personally I agree. I think Europe could do more and in that respect I welcome" the EU summit.
"I hope the outcome will be a stronger European commitment to investing in necessary military capabilities," he reiterated.