The leaders of Britain, France and Germany have agreed the Iran nuclear deal is the best way of stopping Tehran from gaining nuclear weapons, British Prime Minister Theresa May's office said in a statement on Sunday.
May had phone calls with French President Emmanuel Macron and German Chancellor Angela Merkel where they agreed the deal may need to be broadened to cover other areas such as ballistic missiles, what happens when the deal expires, and Iran's destabilising regional activity, the statement said.
"They committed to continue working closely together and with the US on how to tackle the range of challenges that Iran poses – including those issues that a new deal might cover," the statement said.
This comes as a deadline looms next month for President Donald Trump to decide on whether to restore US economic sanctions on Tehran.
Trump has criticised a 2015 agreement which effectively lifted some Western sanctions on Iran in exchange for curbs on its nuclear programme.