President Obama speech at the Brandenburg Gate, Berlin
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US President Barack Obama is to use his public speech in Berlin to propose cuts of one-third in American and Russian nuclear arsenals, US officials say.
In his speech at the Brandenburg Gate, Mr Obama is expected to make what US officials describe as "a call to action", for the West to engage in major global issues.
This is Mr Obama's first visit to Berlin as American president.
Klaus Wowereit, the Mayor of Berlin, and Germany's Chancellor Angela Merkel will speak before the president.