UK Foreign Secretary Boris Johnson has urged US President Donald Trump not to pull out from the Iran nuclear deal, though acknowledging the deal was not perfect, BBC reported.
In televised remarks, Johnson tried to convince Trump who must decide whether to stick with the agreement - which he has called "insane" - by 12 May.
Under the international deal, Iran has limited its nuclear activities in return for eased economic sanctions.
Johnson will not meet the president. But he will meet US Vice-President Mike Pence, National Security Adviser John Bolton and foreign policy leaders in Congress.
The British foreign secretary tried appealing to the president via Fox & Friends, which Mr Trump is known to watch regularly.
Mr Johnson began by saying Mr Trump "is right to see the flaws in" the deal, but he argued they could be fixed.
He also said countries have "got to be tougher on Iran".
But the foreign secretary warned that without the accord, Iran could develop a nuclear weapon and start an arms race among countries in the region.
Mr Johnson concluded that "plan B does not seem, to me, to be particularly well developed at this stage".