Boris Johnson will attempt to persuade United States politicians not to quit the Iran nuclear deal amid a political firestorm at home over his remarks about a British woman jailed in the middle eastern country, News & Star reports.
Ahead of meetings with congressional leaders in Washington DC, Mr Johnson said supporting the agreement does not mean ignoring "disruptive" Iranian behaviour such as the "unjustified detention of British nationals".
The Foreign Secretary's attempts at diplomacy on Iran come with him facing calls to quit over his comments about British woman Nazanin Zaghari-Ratcliffe.
Mr Johnson told a committee of MPs last week that Ms Zaghari-Ratcliffe was training journalists, rather than holidaying, in Iran at the time of her arrest last year, something her employer and family insist is incorrect.
Amid fears his comments may have led the Iranian authorities to try to extend her five-year jail sentence for supposed involvement in a coup plot, Mr Johnson on Tuesday admitted he "could have been clearer" and was "sorry" if his remarks were misconstrued.
He will now spend two days on Capitol Hill for meetings with the likes of US House of Representatives speaker Paul Ryan and majority leader Kevin McCarthy, as well as Senate majority leader Mitch McConnell.
They come after President Donald Trump decertified the Iran deal, giving Congress the power to reimpose economic sanctions on Tehran which were lifted in return for limitations to its nuclear programme.
Mr Johnson will stress the need to stick to the deal to stop Iran developing nuclear weapons.
Speaking at the start of his visit, he said: "The Iran nuclear deal makes the world safer.
"That's why it is vital that the international community sticks to the deal. It is working and has, so far, resulted in Iran giving up 95% of its uranium stockpile.