During the Sunday conversation, which was the second phone call between the two sides within the past few days, Johnson underlined Britain’s support for the nuclear deal.
He also called on all parties to remain committed to the JCPOA.
Johnson’s remarks came after a UK government spokeswoman said Britain and Germany have reiterated their commitment to the landmark 2015 nuclear agreement between Iran and the P5+1 group of countries despite US President Donald Trump’s refusal to certify the deal.
The spokeswoman said in a statement on Sunday that British Prime Minister Theresa May and German Chancellor Angela Merkel in a phone call had “discussed Iran and President Trump’s decision not to certify the nuclear deal.”
“They agreed the UK and Germany both remained firmly committed to the deal,” the spokeswoman said.
The US president laid out the United States’ new strategy on Iran on Friday in which he said he would not certify Iran’s nuclear deal, known as the Joint Comprehensive Plan of Action (JCPOA), signed between Iran and the five permanent members of the United Nations Security Council – the United States, Britain, France, Russia and China – plus Germany.