BERLIN -- U.S. Secretary of State Hillary Rodham Clinton urged Europeans and Americans on Sunday to see the anniversary of the fall of the Berlin Wall as a call to action against new global threats.

On the eve of celebrations marking 20 years since the collapse of the wall that divided East and West Berlin, Clinton said the hard work that went into ending the Cold War must be channeled to meet fresh challenges, including the fights against extremism and climate change.

As the Obama administration looks to often reluctant European allies to bolster their NATO forces in Afghanistan, Clinton said Monday's commemoration of Nov. 9, 1989, the night "when history pierced the concrete and concertina wire," must look forward and not back.

"Our history did not end the night the wall came down, it began anew," she told a group of U.S. and European dignitaries while accepting a Freedom Award on behalf of the American people from The Atlantic Council, a group that promotes trans-Atlantic ties.

The moment the festivities begin "should be a call to action, not just a commemoration of past actions," Clinton said. "That call should spur us to continue our cooperation and look for new ways that we can meet the challenges that freedom faces now."

"We owe it to ourselves and to those who yearn for the same freedoms that are enjoyed and even taken for granted in Berlin today," she said.

Clinton praised U.S.-European collaboration on ending the world financial crisis as well as steps to cooperate on global warming. She also hailed NATO security operations, from Afghanistan to fighting piracy off the coast of Somalia.

But she said the spirit of the Berlin Wall's destruction -- the symbolic end to the Cold War -- had to be reinforced.

"We need to form an even stronger partnership to bring down the walls of the 21st century and to confront those who hide behind them: suicide bombers, those who murder and maim girls whose only wish is to go to school, leaders who chose their own fortune over the fortune of their people."

Clinton will lead the U.S. delegation to Monday's ceremonies in Berlin.

Other speakers at The Atlantic Council event on Sunday were more blunt.

Former U.S. national security adviser Brent Scowcroft, who served under Presidents Ford and George H.W. Bush, lamented that trans-Atlantic cooperation and understanding had fallen off in the two decades since the Berlin Wall fell.

"We no longer have an intimacy of dialogue like we had in 1989," he said. "It's important that we restore that closeness in order that we can all in unity face the challenges confronting us."

Other U.S. foreign policy veterans at the event included former Secretary of State Henry Kissinger and former national security adviser Zbigniew Brzezinski.