Johnson's remarks came on Wednesday at the start of his visit to Washington.
'It took thirteen years of tireless diplomacy between the UK, the US, our European partners and Iran to make the world a safer place,' Johnson was quoted as saying by the official website of the UK Foreign and Commonwealth Office.
'Now it is not the moment to put that at risk,' he added.
During his two-day US visit, which is the first visit to Washington since President Trump’s decision not to certify the Iran nuclear deal under the US domestic legislation, the Foreign Secretary will meet foreign policy leaders from both parties, the UK Foreign and Commonwealth Office said at a press release on Wednesday.
The press release suggested that Johnson will meet senior members of the US Congress to underline the importance of the Iran nuclear deal to global security.
9341**2050
Follow us on Twitter @IrnaEnglish