UNITED NATIONS, Sept 20 (Reuters) - The European Union's foreign policy chief Federica Mogherini said on Wednesday that all parties to the landmark 2015 nuclear deal between Iran and world powers were complying with the agreement.

Mogherini, who spoke at the United Nations after a meeting between the parties, said that any issues outside the scope of the nuclear deal should be dealt with in a different forum.

She added that the United States, which has questioned the value of the deal, agreed that Iran was in full compliance of the agreement. (Reporting by Michelle Nichols and Parisa Hafezi; Writing by Yara Bayoumy; Editing by Sandra Maler)