US Vice-President Dick Cheney has urged European nations to do more to support global democracy and defeat terrorism.
Mr Cheney wants Europe to deploy more troops overseas
He said Europe was key to promoting freedoms in the Middle East which could remove the root cause of terrorism.
But he told business and political leaders that nations had to be prepared to send troops if persuasion failed.
His rare speech outside the United States is part of a concerted effort by Washington to mend transatlantic relations soured by the war in Iraq.
Correspondents say his address to the World Economic Forum in the Swiss ski resort of Davos was a mixture of conciliatory and demanding statements.
Mr Cheney made no apology for the war in Iraq which created a split between the US and its traditional and newer allies such as France, Germany and Russia and still remains a sore point.
"Direct threats require decisive action," he said, adding that the US wanted a strong Europe.
"Just as we must not force you to choose between your European and transatlantic vocations, you must not sell yourselves short and settle for less than the military capability and influence that your people deserve," he said.
We must confront the ideologies of violence at the source, by promoting democracy throughout the greater Middle East and beyond
With the US military stretched in Iraq, Afghanistan and elsewhere, it was "critical" for Europe to step up its troop deployments, the vice-president said.
He noted that Europe and Canada had 1.4 million soldiers under arms, but only 55,000 deployed abroad.
Mr Cheney did acknowledge European efforts to stop the spread of weapons of mass destruction in the Middle East and said there was an urgent need for the US and Europe to co-operate to push for reforms across the Arab world.
"We must confront the ideologies of violence at the source, by promoting democracy throughout the greater Middle East and beyond," he said.
He said greater freedoms would make the world safer from attacks like those of 11 September 2001.
"Democracies do not breed the anger and the radicalism that drag down whole societies and export violence," he said, telling his audience that Europe itself had moved on from conflicts to peace and prosperity.
He made particular reference to the situation in Iran, where a political crisis has developed over attempts by the conservative Guardians Council to exclude reformists from forthcoming parliamentary elections.
"We call for the Iranian regime to honour the legitimate demands of the Iranian people," he said. "There are growing calls for true democracy and human rights."
His comments follow a Friday sermon by Ayatollah Ahmad Jannati, head of Iran's Guardians Council, in which he scolded the US and European nations for "interference".
BBC News Online's Tim Weber, reporting from Davos, says anticipation had been high in the run-up to the speech, and participants were unanimous that it demonstrated the US administration was reaching out to its allies.
However, a quick straw poll in the audience afterwards showed that many would have liked the vice-president to go further.
Eva Biaudet, a Finnish MP and former health minister, said the vice-president had failed to touch upon key issues like "poverty, injustice and development", while she was shocked by what she called Mr Cheney's "militaristic view of how to get democracy".
US Congressman Sander Levin, a Michigan Democrat, said that while he agreed with the basic sentiment of Mr Cheney's remarks, "he did not do well in addressing the issues that actually bother people... like how unilateral US action fits in with the concept of collegiality" set out in the speech.