The outgoing USinfo-icon President Barack Obama urged his successors on Monday to remember that last year's nuclear deal with Iraninfo-icon was the results of years of hard work.

In a message marking the first anniversary of the Iran nuclear deal's implementation, Mr Obama warned that the challenges the US faces today would be much worse without the agreement.

"The United Statesinfo-icon must remember that this agreement was the result of years of work, and represents an agreement between the worldinfo-icon's major powers -- not simply the United States and Iran," he said.

The incoming Trump administration, which takes charge on Jan 20, has said that it would re-examine the deal and may demand more restrictions on Iran. The Iranian government, however, has indicated that it may walk out of the deal if the United States imposed new conditions.

The deal, known as the Joint Comprehensive Plan of Action (JCPOA), was reached between the United States, Franceinfo-icon, the United Kingdominfo-icon, Germanyinfo-icon, Chinainfo-icon, Russiainfo-icon, the European Unioninfo-icon and Iran. It places specific limits on Tehraninfo-icon's nuclear programme in exchange for easing global oilinfo-icon, trade and financial sanctions.

President Obama said that the Iran deal must be measured against the alternatives, which could have led to an armed conflictinfo-icon with Iran.

"A diplomatic resolution that prevents Iran from obtaining a nuclear weapon is far preferable to an unconstrained Iranian nuclear programme or another warinfo-icon in the Middle Eastinfo-icon," he said.

Mr Obama claimed that the deal had already achieved significant, concrete results in making the United States and the world a safer place.