The U.S. ambassador in London is urging Britain to back President Donald Trump in pulling out of the Iran nuclear agreement, saying a united front is the best way to persuade Tehran to change its course.

Ambassador Robert Wood Johnson wrote in the Sunday Telegraph that “we are asking global Britain to use its considerable diplomatic power and influence and join us as we lead a concerted global effort towards a genuinely comprehensive agreement.”

Trump pulled out of the deal in May and last week began reinstating economic sanctions against Iran that were eased in exchange for concessions on Iran’s nuclear program.

The U.K., France, Russia, China, Germany and the European Union, which also signed the deal, have criticized Trump’s decision and continue to back the agreement with Iran.

(AP)