UPDATE 1-Iran nuclear deal parties committed, though 'increasingly difficult' -EU envoy

By John Irish

(Adds envoy quote, context)

By John Irish

UNITED NATIONS, Sept 25 (Reuters) - The remaining parties to the Iran nuclear deal are committed to preserving the pact though it is "increasingly difficult," European Union foreign policy chief Federica Mogherini told reporters after a meeting of the parties at the United Nations.

The 2015 pact curbed Iran’s disputed nuclear program in exchange for relief from sanctions, but has unraveled since the United States pulled out of it last year and acted to strangle Iran’s oil trade to push it into wider security concessions.

"It is in the interests of all to remain committed to the deal, but it is becoming increasing difficult," Mogherini said.

She said France, Britain, Germany, Russia, China and Iran had agreed to continue efforts to implement the deal, which U.S. President Donald Trump withdrew from in May 2018.

Since May this year, Iran has begun to exceed limits on its nuclear capacity set by the pact in retaliation for U.S. pressure on Iran to negotiate restrictions on its ballistic missile program and support for proxy forces around the Middle East.

Iran says its measures are reversible if European signatories to the accord manage to restore its access to foreign trade promised under the nuclear deal but blocked by the reimposition of U.S. sanctions.

Iran says that if it does not receive economic benefits from the deal by November it will further reduce its commitments.

"Every step that has been taken so far by Iran is reversible and we call on Iran to reverse these decisions and go back to full compliance," Mogherini said. "I hope that rationality will prevail." (Reporting by John Irish, writing by Michelle Nichols; editing by Grant McCool)