"They agreed on the importance of the international community coming together to counter Iran's destabilising regional activity, and the Prime Minister reiterated the UK's commitment to the Iran nuclear deal," the prime minister's spokesperson said, as quoted by the Independent newspaper.
According to the Downing Street representative, May and Tillerson also discussed "the continuing depth and breadth of the special relationship" during the talks in London.
READ MORE: Netanyahu: Europe Must Preserve Nuclear Deal With Iran
The Joint Comprehensive Plan of Action, agreed in 2015, ensures the gradual lifting of sanctions off Iran in exchange for Tehran ensuring that its nuclear program is peaceful. US President Donald Trump has repeatedly criticized the deal and Iran's compliance with it.