John Sawer, Britain's representative at the talks, was also quoted as saying that "some good progress" was made at the London meeting today.
The London talks include representatives from UN Security Council permanent members -- China, Russia, the United States, France, and Britain -- as well as Germany.
McCormack also said that Iran recently has sought bilateral talks with Washington, but said the U.S. administration will stick with the multilateral approach aimed at persuading Tehran to abandon its nuclear program.
RFE/RL Iran Report
SUBSCRIBE For regular news and analysis on Iran by e-mail, subscribe to "RFE/RL Iran Report."