US President George W Bush has said he wants to resolve the Iranian nuclear crisis through peaceful means.
After talks in Washington with German Chancellor Angela Merkel, Mr Bush said both leaders sought to solve the issue "diplomatically by working together".
President Bush refused to be drawn on whether the UN Security Council should impose sanctions on Iran.
Iran insists it has a right to peaceful nuclear technology and denies seeking atomic weapons.
It has threatened to halt snap inspections of its nuclear facilities and resume uranium enrichment if the issue is sent to the Security Council.
Ms Merkel - on her first US visit since taking office - said Europe and the US must take a united stand on Iran.
On Thursday, the German, French and British foreign ministers called for the UN to deal with Iran's nuclear programme.
But, in a sign of divisions within the international community over how to proceed, China's UN ambassador Wang Guangya warned on Friday that referring Iran to the Security Council "might complicate the issue".
Mr Bush said it was "logical that a country which has rejected diplomatic entreaties" be sent to the Security Council, which has the power to impose sanctions.
He said the US, Germany and other nations needed to "send a common message to the Iranians... to not have a nuclear weapon to blackmail or threaten the world."
IRAN'S NUCLEAR STANDOFF
Sept 2002: Work begins on Iran's first reactor at Bushehr
Dec 2002: Satellites reveal Arak and Natanz sites, triggering IAEA inspections
Nov 2003: Iran suspends uranium enrichment and allows tougher inspections
June 2004: IAEA rebukes Iran for not fully co-operating
Nov 2004: Iran suspends enrichment under deal with EU
Aug 2005: Iran rejects EU plan and re-opens Isfahan plant
Jan 2006: Iran re-opens Natanz facility
Asked if he expected sanctions to be imposed on Iran, Mr Bush said he was "not going to prejudge what the United Nations Security Council should do".
"What you're seeing is the evolution of a proactive diplomatic policy," he said.
The BBC's Justin Webb in Washington says the sense of impatience for action, which was palpable before the Iraq war, does not exist over Iran.
What the White House wants though, is allies who are willing to talk tough and willing to face up to the possibility of confrontation with Iran at some stage in the future, he adds.
The two leaders said they had discussed the Iran issue at length.
Chancellor Merkel said Iranian President Mahmoud Ahmadinejad's call for the annihilation of Israel was "totally unacceptable", adding: "We will not be intimidated by a country such as Iran."
The chancellor has said she wants to improve relations with the US, after ties soured under her predecessor, Gerhard Schroeder, a fierce opponent of the US-led war in Iraq.
Our correspondent says that on Iran, there is at the moment no serious division, and President Bush seems to feel that he has an ally he can trust in Berlin - something he has not felt for years.