UK backs Iran nuclear deal despite US objections

British Foreign Secretary Boris Johnson has urged all parties to uphold their commitments to the Iran nuclear deal, describing it "a historic achievement".

Johnson's remarks followed phone calls with U.S. Secretary of State Rex Tillerson and Iranian Foreign Minister Javad Zarif yesterday.

However, U.S. commitment to maintaining the deal struck under former President Barack Obama has been cast into doubt by current American leader Donald Trump who is opposed to the international compromise package.

His administration plans to announce its decision on the 2015 nuclear deal between Iran and six major world powers. Trump is expected to decertify the agreement.

However, British remains supportive of the deal, which took 13 years to hammer out. "The nuclear deal was a crucial agreement that neutralized Iran's nuclear threat," Johnson said on Wednesday.

"The U.K. supports the deal and stresses the importance of all parties continuing to uphold their commitments," he added. "It was the culmination of 13 years of painstaking diplomacy and has increased security, both in the region and in the U.K."

"We have made no bones about our deep concern at Iran's destabilizing regional activity, including its ballistic missile program, but I remain steadfast in my view that the nuclear deal was an historic achievement that has undoubtedly made the world a safer place," Johnson also said.

He will meet Iranian Vice President Ali Akhbar Salehi in London to press for Iran's continued compliance with the deal.

British Prime Minister Theresa May, who spoke by telephone to Trump about the agreement on Tuesday, also reaffirmed the U.K.'s "strong commitment to the deal alongside our European partners".

Salehi, who is also head of Iran's nuclear agency, will come to London on Wednesday following a nuclear conference in Rome.