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Mayor Bill de Blasio received a standing ovation after his speech at the British Labour Party’s annual conference Wednesday in Manchester, England.

De Blasio Walks Tightrope Between Municipal Politics and International Influence

By MICHAEL M. GRYNBAUM

Mayor Bill de Blasio of New York, a virtual unknown not so long ago, is now determined to cultivate a profile on the international stage.

Former Mayor Rudolph W. Giuliani, a Republican, said that Mr. de Blasio had been unfairly criticized for his foreign travel, noting that the job demanded fluency in international affairs.

“When I ran for president, they challenged me on how much I knew about foreign policy,” Mr. Giuliani said. “I said I thought I knew more about foreign policy than most congressmen or senators.”