UK Prime Minister Theresa May stressed the importance of the Iran nuclear accord to US President Donald Trump in a phone call on Tuesday.
May emphasised that the deal needs to be "carefully monitored and properly enforced", just days before the president is expected to announce whether he will scrap the deal.
"The (prime minister) reaffirmed the UK's strong commitment to the deal alongside our European partners, saying it was vitally important for regional security," said a statement from May's office.
"(The prime minister) stressed that it was important that the deal was carefully monitored and properly enforced," it added.
Signed between Iran and world powers in 2015, the accord saw Tehran reduce its nuclear programme in exchange for sanctions relief.
Trump, however, has long been a critic of the deal, recently claiming that it does not serve US interests.
It has been anticipated that the US president will announce the end of the deal this week, however Prime Minister May reportedly received assurances that the UK will be kept in contact prior to a decision, according to the BBC.
A White House statement on the phone call, meanwhile, described the discussion as one in which Trump "underscored the need to work together to hold the Iranian regime accountable for its malign and destabilising activities, especially its sponsorship of terrorism and its development of threatening missiles".
Trump has in recent times argued that Iran is in breach of the deal's terms. The UK, however, has upheld that Iran is acting in accordance with the accord, despite engaging in "destabilising activities".
"We have made no bones about our deep concern at Iran's destabilising regional activity," UK Foreign Secretary Boris Johnson said on Tuesday. "But I remain steadfast in my view that the nuclear deal was an historic achievement that has undoubtedly made the world a safer place."
