Prime Minister Gordon Brown and German Chancellor Angela Merkel backed renewed efforts to secure fresh sanctions on Iran over its nuclear programme during wide-ranging talks.
The pair met at Mr Brown's official country retreat Chequers, where they both expressed "strong support" for sanctions, Downing Street said.
It came as a senior US diplomat signalled China was ready to hold "serious" talks at the United Nations with Western powers which reject Tehran's claims not to be seeking nuclear weapons.
China wields a veto as a permanent member of the UN Security Council but US President Barack Obama has said he hopes to have new sanctions in place within weeks.
A Number 10 spokesman said: "The Prime Minister and Chancellor Merkel had an excellent discussion at Chequers which focused on foreign policy and the world economic situation.
"One year on from the London G20, they discussed the steps necessary to ensure another successful G20 summit in June. They also had a long discussion on climate change in advance of the Bonn meeting, and talked about the latest developments in the Middle East peace process.
"On Iran, there was strong support from both leaders for sanctions, and agreement on the continued need to engage with international partners on the issue."
