Berlin —- Barack Obama stood before a sea of people here Thursday and issued a call for cooperation, imploring America and Europe to bridge differences and rekindle old alliances in an effort to restore global stability and better confront existing and unforeseen threats.

"If we're honest with each other, we know that sometimes, on both sides of the Atlantic, we have drifted apart and forgotten our shared destiny," Obama said. "In Europe, the view that America is part of what has gone wrong in our world, rather than a force to help make it right, has become all too common. In America, there are voices that deride and deny the importance of Europe's role in our security and our future."

Pausing for a moment, he added: "Both views miss the truth."

The presumptive Democratic presidential nominee delivered his address at the base of the Victory Column in the Tiergarten, a sprawling park in the center of the city.

He looked out toward the Brandenburg Gate, where President Ronald Reagan implored the Soviet leader Mikhail Gorbachev to "tear down that wall" and end the Cold War, as he spoke to an estimated 200,000 people.

"I come to Berlin as so many of my countrymen have come before," Obama said. "Tonight, I speak to you not as a candidate for president, but as a citizen —- a proud citizen of the United States, and a fellow citizen of the world."

Obama, as he visits the Middle East and Western Europe, is eager to prove himself on a worldwide stage as a potential leader of the United States. He seemed intent on trying to achieve two goals —- healing the wounds left by the Bush administration and presenting an image to voters at home as a president whom the world could embrace.

Linking the battle against terrorism to the struggle of the Cold War that defined this city for decades, Obama spoke directly on the need for more soldiers to fight in Afghanistan, a politically unpopular stance here.

He did not overtly criticize President Bush or his presumptive Republican opponent, John McCain, but he did offer some criticism of his own nation.

"I know my country has not perfected itself," he said. "We've made our share of mistakes, and there are times when our actions around the world have not lived up to our best intentions. But I also know how much I love America."

Manfred Krause, 65, a retired citizen of the former East Germany, said Obama's address brought back memories of the Rev. Martin Luther King Jr.'s 1964 visit to East Berlin. "I thought, here is someone coming from the same place," he said.

Yet the most important audience was watching in the United States. The television images, which showed Germans and others waving American flags, created a curious tableau that Republicans sought to seize on.

On the other side of the Atlantic, McCain —- gently mocking Obama by campaigning at a German restaurant in Ohio —- criticized his opponent for traveling to Germany to speak.

"I'd love to give a speech in Germany —- a political speech or a speech that maybe the German people would be interested in," he said, "but I'd much prefer to do it as president of the United States rather than as a candidate."