Russia says it will do everything possible to keep the 2015 Iran nuclear deal alive after the US chose to unilaterally abandon the international agreement, vowing continued trade cooperation with Tehran despite the return of American sanctions.

The Russian Foreign Ministry made the comments in a statement quoted by the Interfax news agency on Thursday without further details.

In early May, the administration of US President Donald Trump pulled the country out of the nuclear agreement, dealing a blow to the outcome of years of international diplomacy and teamwork.

The White House also said it would impose the "highest level of" economic sanctions against Iran.

The other parties to the deal -- along with the entire world community -- harshly censured Trump's decision, expressing their determination to keep honoring the deal and make efforts, at the same time, to save the historic agreement without the US.

Tehran has said it will not leave the deal, officially named the Joint Comprehensive Plan of Action (JCPOA), for now, but conditioned its stay in the pact on a set of practical EU measures aimed at protecting Iran's share of dividends from the accord when Washington's sanctions snap back into place.

Since then, Iran and other parties to the deal -- Russia, China, France, Britain plus Germany -- have been engaged in a flurry of diplomatic contacts to find ways to save the JCPOA.

The European parties to the deal are currently working to finalize a package of proposals meant to blunt the impact of returning US sanctions on their businesses in Iran and safeguard their commercial ties with Tehran.

Russia has, in turn, said it will develop even closer ties with Iran in the wake of Washington's pullout from the deal.

Vladimir Yermakov, Director General of the Department for Non-Proliferation and Arms Control at Russia’s Foreign Ministry, had said in early May that with the US exit “it might even be easier for us on the economic front, because we won’t have any limits on economic cooperation with Iran. We would develop bilateral relations in all areas – energy, transport, high tech, medicine."

Not only did the US fail to honor its side of the bargain with Iran, but it has also been seeking to throw a wrench in efforts by the remaining parties to the deal to fulfill their obligations under the JCPOA, which has been endorsed by UN Security Council 2231.

Washington has threatened the European firms with hefty penalties should they refuse to leave Iran with the return of American sanctions.

Russia’s Envoy to International Organizations in Vienna Mikhail Ulyanov said on Wednesday the US “discredited itself by proving to be an unreliable partner."

He also praised Iran for its “wise and balanced” approach in dealing with Washington and its attempt to keep its side of the agreement.

Moscow's statement comes as foreign ministers of Iran and its remaining partners -- now known as 4+1 states -- are set to hold a meeting on the fate of the JCPOA following Washington's exit.