UK Prime Minister Tony Blair and German Chancellor Angela Merkel have vowed to keep up strong diplomatic pressure on Iran over its nuclear programme.
The two leaders said they were united on the Iran issue
After talks in Berlin, Mr Blair said the issue should be tackled "strongly but through the diplomatic means".
Ms Merkel again said Iran had "crossed the red line" by resuming its controversial programme this month.
Mr Blair also rejected Iran's call to withdraw UK troops from southern Iraq, saying the troops had "a UN mandate".
Tehran's demand for the British pullout from the city of Basra was voiced earlier on Friday by Iranian Foreign Minister Manouchehr Mottaki.
The talks in Berlin came a day after France accused Iran of having a secret programme for developing nuclear weapons - prompting Mrs Merkel to warn Tehran that it was isolating itself internationally.
Iran had resumed small-scale uranium enrichment after it was reported to the UN Security Council earlier this year.
Tehran had also banned snap inspections of it sites by international nuclear experts.
Western nations suspect Iran is attempting to build nuclear weapons. Iran insists its nuclear programme is solely for peaceful purposes.
The UN Security Council is due to meet in March to discuss the next steps, which could lead to sanctions against Iran.
Mrs Merkel said in Berlin that the time "window" before that meeting should be used to try to resolve the situation.