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President Obama renewed his push for a reduction in the world's nuclear stockpiles during a wide-ranging speech in Berlin on Wednesday, claiming the U.S. could continue to maintain a strong deterrent while ultimately striving toward eliminating nuclear weapons.

"So long as nuclear weapons exist, we are not truly safe," Obama said.

Speaking at the Brandenburg Gate, Obama proposed a one-third reduction in U.S. and Russian strategic nuclear warheads. This would lower the total number of warheads in each country to between 1,000 and 1,100.

The potential reductions would be from a current limit of 1,550, the number set in the New START treaty that was ratified by the Senate in December 2010.

Though Obama is likely to meet some resistance in Congress to further eroding America's stockpile, the president held out what he acknowledged was a "distant" goal of ridding the world of nuclear weapons -- and in the short term, moving beyond "Cold War nuclear postures."

He addressed the nuclear reduction effort during a speech that focused in large part on Germany's and Berlin's tumultuous history. To the symbolic backdrop of the Brandenburg Gate, Obama lauded German citizens who chose "whether to be defined by a wall or whether to tear it down."

The president also reprised his high-profile appearance in the German capital during his 2008 presidential race. The crowd on Wednesday was far smaller, and also at a different venue. German Chancellor Angela Merkel denied him the option of speaking at the Brandenburg Gate in 2008, saying only sitting presidents were granted such an honor.

As Obama addressed German history and the nuclear issue, he also covered a series of what some might call lofty goals -- tackling climate change, closing Guantanamo Bay and ending AIDS.

Obama tried to make the case that even though the Berlin Wall came down 23 years ago and the threat of nuclear war has dissipated, the type of activism apparent during the Cold War needs to be applied to such current challenges as climate change, counterterrorism and the push for democratic values beyond the United States and Europe.

Obama did not propose any timeline for achieving the proposed nuclear cuts.

Obama is fresh from a two-day summit of the Group of Eight industrial economies. He discussed nuclear non-proliferation with Russian President Vladimir Putin during their meeting Monday on the sidelines of the international summit in Northern Ireland.

A senior administration official said Obama was also renewing his call for Congress to ratify a stalled nuclear test ban treaty.

The Associated Press contributed to this report.