Gates, a former CIA director who witnessed the collapse of the Soviet Union, responded with wry humor and a history lesson to Putin who portrayed the United States in a speech here Saturday as a dangerous, destabilizing world power.

"Speaking of issues going back many years, as an old Cold Warrior, one of yesterday's speakers almost filled me with nostalgia for a less complex time. Almost," Gates said in a speech to the same international security conference.

"I have, like your second speaker yesterday, a starkly different background -- a career in the spy business. And I guess old spies have a habit of blunt speaking," he said.

Re-education for a Cold Warrior

But in his debut speech as US defense chief, Gates said he had gone to "re-education camp" as a university president where he learned in dealing with academic faculties that it is either "be nice" or "be gone."

Gates said the world today is different and more complex than during the Cold War era, and partnerships with other countries, including Russia, were needed to face common problems and a new challenge from Islamic extremism.

He said he had accepted an invitation from Putin and Russian Defense Minister Sergei Ivanov to visit Russia.

'Rumsfeld's "Old Europe" belongs to the past'

The new US defense secretary also made a passing but pointed reference to his predecessor, Donald Rumsfeld, who antagonized European powers by dividing the NATO alliance into countries that supported the US invasion in Iraq and those who did not.

"Over the years, people have tried to put the nations of Europe and of the Alliance into different categories -- the 'free world' versus 'those behind the Iron Curtain', 'North' versus 'South', 'East' versus 'West,'" he said. "And I am told that some have even spoken in terms of 'old' Europe versus 'new.'"

"All of these characterizations belong to the past," he said.

"Looking back, it seems clear that totalitarianism was defeated as much by ideas the West championed -- now and then -- as by ICBMs (intercontinental ballistic missiles), tanks and warships that the West deployed," he said. "Our most effective weapon, then and now, has been Europe and North America's shared belief in political and economic freedom, religious toleration, human rights and representative government and the rule of law," he said.

"Today they are under threat by another virulent ideological adversary and are confronted by a range of other looming geopolitical challenges," he said.

Energy for political coercion

Putin on Saturday stunned top officials and academics gathered in Munich with a vehement attack on US leadership in the world. A former KGB spy, Putin charged that United States has "overstepped its borders in all spheres," creating a dangerous "uni-polar" world that had brought war, ruin and insecurity.

He questioned the intentions behind NATO expansion eastward into countries that once formed part of the Soviet Union, and US plans for missile defense systems in Poland and the Czech Republic, former Soviet bloc states.

Gates in contrast said Russia was "a partner in endeavors."

"But we wonder, too, about some Russian policies that seem to work against international stability, such as its arms transfers and its temptation to use energy resources for political coercion," he said.

Russia "need not fear law-based democracies on its border," he added.

Exporting security

Gates identified violent extremism "grounded in a profound alienation from the foundations of the modern world" as a challenge "unlike anything the West has faced in many generations."

"No fewer than 18 terrorist organizations, many linked with al-Qaeda, have pulled off bloody attacks throughout the world," he said. "Those attacks -- and other threats that have since emerged -- revealed even more starkly the need to reorient the Atlantic alliance to be able to export security beyond the borders of NATO," he said.

He stressed the importance of not allowing success in Afghanistan to slip away.

Other challenges he cited included sectarian conflicts and jihadist movements radiating out from Central Asia and the Middle East; an Iran "with hegemonic ambitions seeking nuclear power;" and the struggle over the future of Iraq.

He also said China was at a "strategic crossroads."

"All of us seek a constructive relationship with China, but we also wonder about strategic choices China may make," he said. "We note with concern their recent test of an anti-satellite weapon."