Germany's foreign minister appealed to Iran to ease tensions over its seizure of 15 British military personnel and condemned Teheran's decision to show some of the captives on television, according to comments released Saturday. "The 15 soldiers must be freed; British diplomats must immediately be able to speak with those arrested," Frank-Walter Steinmeier wrote in a guest article for the Bild am Sonntag newspaper, released on Saturday by the weekly. "If the leadership in Teheran thinks that anyone views this action as a demonstration of strength, it is mistaken," Steinmeier wrote, according to Bild am Sonntag. "I appeal to the leadership in Teheran to defuse the tense situation. There must not be a further intensification."