EU foreign ministers have agreed to implement sanctions against Iran after its refusal to halt uranium enrichment.
The EU wants to get Iran back to the negotiating table
The sanctions go further than those already agreed by the United Nations.
The UN sanctions involve a partial arms embargo and a travel ban against people and organisations involved in Iran's nuclear programme.
The EU has agreed a total arms embargo, and added further people to the travel ban list - they are banned from the EU and their assets are frozen.
At the same time, the EU foreign policy chief, Javier Solana, has announced that he will fly to Turkey on Wednesday for talks with Iran's top nuclear negotiator, Ali Larijani.
This will be the first time the two men have met since early February.
Mr Solana made no mention of what he hopes to come out of the discussions, given the international insistence that Tehran must freeze its nuclear enrichment programme before full negotiations can begin.
The BBC's Michael Voss in Luxembourg says the EU has been adopting a carrot and stick approach - tougher sanctions on the one hand, with major economic and political enticements and co-operation in the civil nuclear sector.
So far though, the results have been limited, he says.
On Sunday an Iranian foreign ministry spokesman said that the country had no intention of halting uranium enrichment.
During the two-day meeting, the ministers will also hold talks with their Russian counterpart to review the increasingly troubled Moscow-EU ties.
Relations have been strained over trade, energy and political issues.
The future of Kosovo is also set to be raised in the ministers' meeting with Russian Foreign Minister Sergei Lavrov.
Over the weekend the EU failed to resolve Moscow's ban on Polish meat exports.
This could have serious implications for next month's EU-Russian summit, with Poland having so far vetoed moves to negotiate a new co-operation and energy pact with Moscow.