Democratic presidential candidate Senator Barack Obama waves as he arrives at the Victory Column in Berlin, yesterday. - AP

WASHINGTON (AP):

Tens of thousands of Germans stood below a Berlin war memorial yesterday listening as Democratic presidential contender Barack Obama issued an impassioned call for the world's people to unite in their common humanity.

Recalling Berlin's history as a divided city and the front line of the Cold War, Obama said Europeans and Americans must close ranks to "defeat terror and dry up the well of extremism that supports it'', the same as they beat back the Communist challenge in the generations after World War II.

Acknowledging recent strains in the Atlantic alliance and grave differences with Germany over the United States invasion of Iraq, Obama said, "partnership and cooperation among nations is not a choice; it is the one way, the only way, to protect our common security and advance our common humanity.''

Berlin police estimated the crowd at the base of the Victory Column in the Tiergarten park in the heart of the city at more than 200,000.

'Walls cannot stand'

"The walls between old allies on either side of the Atlantic cannot stand,'' Obama said, speaking not far from where the Berlin Wall once sliced across the city. "The walls between the countries with the most and those with the least cannot stand. The walls between races and tribes, natives and immigrants, Christian and Muslim and Jew cannot stand.''

Obama said he was speaking as a citizen of the United States and the world, not as a president, but the evening was redolent with American politics, drawing obvious comparisons to historic Berlin speeches by Presidents John F. Kennedy and Ronald Reagan.

"People of Berlin, people of the world, this is our moment. This is our time,'' Obama said.

Earlier, Obama, who has vowed greater consultation with American allies on major foreign policy issues, auditioned for that role in a meeting with conservative German Chancellor Angela Merkel.