The announcement by Ban Ki-moon , the United Nations secretary general, that he had invited Iran to a peace conference to end the war in Syria drew strong objections on Sunday from American officials, who suggested that Iran had not met all the conditions for attending and that the invitation might need to be withdrawn. At the heart of the dispute is whether Iran has accepted the terms of the talks, which begin Wednesday in Montreux, Switzerland: to establish “by mutual consent” a transitional body to govern Syria. Mr. Ban said he had been privately assured that Iranian officials “welcome” those rules and that they had pledged to play “a positive and constructive role.” American officials said they had been in regular communication with the United Nations over the requirements Iran would need to meet to be invited, but they appeared to have been caught off guard by Mr. […]