Taking the world stage once again, President Obama attempted to build a global consensus Friday on the need to collectively confront nuclear proliferation, recession, terrorism, poverty and drug trafficking.

Obama spoke first to a large crowd of French and German citizens, many of whom were students, at a town hall-style meeting in Strasbourg, France, ahead of a major NATO summit. He then spoke alongside German Chancellor Angela Merkel in Baden-Baden, Germany

In his Strasbourg speech, delivered before taking questions from the audience, Obama invoked the slogans of his presidential campaign and stressed U.S.-European unity -- much as he did during his pre-election speech in Berlin over the summer. Whereas many U.S. presidents have strived during their time in office to build a domestic consensus, Obama further demonstrated his commitment to leading a new era of cooperation around the world.

"This is our generation, this is our time and I am confident we can meet any challenges as long as we are together," Obama said.

He drew huge applause when he said he is setting a dramatic goal of "a world without nuclear weapons."

He said he would outline details in Prague in the coming days.

"Even with the Cold War now over, the spread of nuclear weapons or the theft of nuclear material could lead to the extermination of any city on the planet," Obama said. "There's no corner of the globe that can wall itself off from the threats of the 21st century."

He cited the commitment he and Russian President Dmitry Medvedev announced two days ago to draw down their nuclear stockpiles -- a move he said would give the U.S. "moral authority" to demand Iran and North Korea stop their nuclear activity.

Further underscoring his president-for-all-people image, Obama even apologized for apparently calling on an American by accident to ask the first question.

"I just want to say, I did not call on the American on purpose," Obama said.

Obama comes to France and Germany after hammering out an agreement with leaders of the G20 nations in London on how to confront the global economic crisis. 

"If we do not have concerted action, then we will have collective failure. I'm very proud of the work that was done in London," he said in Germany. 

Obama said earlier at his town hall that the United States shares blame for the crisis, but that "every nation bears responsibility for what lies ahead -- especially now."

Obama opened the appearance -- in a sports arena and before a French and German audience heavily made up of students -- with several minutes of prepared remarks read from a Teleprompter. In them, he underscored the importance of the relationship between Europe and America, and he encouraged Europe to support his retooled strategy to root out terrorism in Afghanistan and Pakistan.

"I understand this war has been long. Our allies have already contributed greatly to this endeavor," Obama said. "Understand we would not deploy our own troops if this mission was not indispensable to our common security ... I understand there's doubt about his war in Europe. There's doubt even in the United States."

But he said the U.S. and its allies must continue to go after terrorist to ensure a safer world.

Obama bluntly said the relationship between the United States and Europe has gone adrift, with blame on both sides.

In America, he said, "there's a failure to appreciate Europe's leading role in the world."

"There have been times when America's shown arrogance and been dismissive, even derisive," Obama said.

The Associated Press contributed to this report.