PA -- Nato must retain its primacy in the defence of Europe, Defence Secretary Liam Fox will say.
It would be "nonsense" to develop an EU defence capacity duplicating the North Atlantic alliance, which is a "necessity" because it ensures US engagement in Europe, Dr Fox will tell the Conservative conference in Manchester.
And he will accuse some countries which are calling for greater EU defence integration of falling short on their existing commitments to Nato.
The UK is one of a handful of Nato states to live up to the alliance's target of spending 2% of national income on defence.
Dr Fox was due to fly to Brussels following his speech to take part in a two-day summit of Nato defence ministers, where he will discuss European defence, Libya and Afghanistan.
He will tell Tory activists: "There are those in Europe who are calling for the EU to take a greater role in Europe's security.
"Let me tell you, Europe already has a guarantor of its defence - it's called Nato.
"It is nonsense to duplicate and divert from Nato at a time when resources are scarce across Europe. And the last thing we need is more EU bureaucracy.
"You know, many of those calling for deeper EU defence integration are already failing to fulfil their commitments to Nato. You cannot expect to have the insurance policy but ask others to pay the premiums.
"Nato must maintain its primacy in European defence because Nato is the alliance that keeps the United States in Europe. This not a luxury, it is a necessity."