The United States and China are united against Iran becoming a nuclear weapons state, US Secretary of State Hillary Clinton has said after high-level talks with a team from Beijing.
Clinton told reporters she was "pleased that China shares our concerns about Iran becoming a nuclear weapons state."
Both nations fear that a nuclear-armed Iran would trigger a regional arms race, Clinton said after the two days of talks.
"The potential for destabilising the Middle East and Gulf is viewed similarly," Clinton said on Tuesday.
Clinton said that the two nations also shared in-depth discussions on how to make progress with North Korea.
China is the closest ally of North Korea, which in recent months has tested a nuclear bomb, fired missiles and stormed out of a disarmament deal.
In a joint statement, the two nations agreed to work together ahead of next year's meeting to review the nuclear Non-Proliferation Treaty - a key issue for President Barack Obama who has set an ambitious goal of abolishing nuclear weapons.
"Both sides noted their shared opposition to terrorism and pledged to work collaboratively to strengthen global non-proliferation and arms control regimes," the joint statement said.