FILE PHOTO: German Foreign Minister Heiko Maas attends a news conference in Ankara, Turkey September 5, 2018. REUTERS/Umit Bektas

BERLIN (Reuters) - The United States’ strategy of applying maximum pressure on Iran will not work alone and carries the risk of a regional escalation, Germany’s Foreign minister Heiko Maas said.

“If fronts harden, nothing will get better or easier, but much more dangerous and difficult,” Maas said following a meeting with Britain, China, France, Germany, Russia and Iran in New York on Monday to discuss Iran’s nuclear deal.

The remaining parties to the Iran nuclear deal on Monday agreed to keep working to maintain trade with Tehran despite scepticism this is possible as U.S. sanctions to choke off Iranian oil sales resume in November.