Diplomats said the EU foreign ministers meeting in Brussels would officially adopt the measures later Monday, now that the details had been hashed out by the 27 ambassadors to the EU. The measures include an immediate ban on new contracts for Iranian crude oil and petroleum products, while existing contracts will be allowed to run until July.
"I am confident that the EU will give a resolute answer today to Iran's refusal to fulfill its international obligations on the nuclear program,» German Foreign Minister Guido Westerwelle said, in anticipation of the official adoption by the foreign ministers.
Iran says its nuclear program is exclusively for peaceful purposes, but many international officials fear the country is trying to develop nuclear weapons.
The EU will also likely freeze the assets of the Iranian central bank.
"The pressure of sanctions is designed to try and make sure that Iran takes seriously our request to come to the table,» EU foreign policy chief Catherine Ashton said.
In October, Ashton sent a letter to Saeed Jalili, Iran's top nuclear negotiator, saying her goal was a negotiated solution that «restores international confidence in the exclusively peaceful nature of Iran's nuclear program."
She says she has not yet received a reply.
British Foreign Secretary William Hague said the goal of the sanctions would be to «increase the peaceful, legitimate pressure» on Iran to return to negotiations.
Negotiators have worked hard to try to ensure that the embargo punishes only Iran - and not EU member Greece, which is in dire financial trouble and relies heavily on low-priced Iranian oil.
EU negotiators have agreed to a review of the effects of the sanctions, to be completed by May 1, a diplomat said. He spoke on condition of anonymity to discuss the subject of ongoing talks.
"It is important to know what will happen to individual countries as a consequence of the sanctions,» Ashton said.
Westerwelle said it was critical that action be taken.
"This is not a question of security in the region,» he said. «It is a question of security in the world.»