Rodman was in Pyongyang on a trip with the Harlem Globetrotters.
Kim Jong-un, who is a basketball fan, was told by Rodman that he had made "a friend for life."
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The signs were encouraging to commuters going about the transport network the day after a terror attack in Westminster.
Faith leaders from across London say religious communities will "stand together" in the wake of the Westminster terror attack.
Pc Keith Palmer was among the three people killed yesterday in the Westminster terror attack.