"We are consulting our members to evaluate" it, a spokesman for European refiners association Europia said, a sign that the oil industry is starting to take precautionary steps in case an embargo is implemented.

EU foreign ministers broadened sanctions against Iran on Thursday due to "serious and deepening concerns" about the country's nuclear program. While the meeting didn't result in an oil embargo, EU officials emphasized that such a move had strong support in Brussels.

EU foreign policy chief Catherine Ashton said an oil embargo was still "being debated," and diplomats said some restrictions on Iranian oil imports were likely to be imposed in the coming months.

The EU said it would examine further embargoes on Iran's energy, banking and transport sectors and make a decision by its next meeting of foreign ministers in January.

"The EU made very clear that it will not bow to Iran's intimidation and bullying tactics," British Foreign Secretary William Hague said on Thursday.

Proponents of the embargo said they were working to address the concerns of Greece and some other countries that fear an embargo would push prices up at a time when their economies are already struggling.

Iran exported 870,000 barrels a day to Europe in the second quarter, mostly to Spain, Italy and Greece, according to the International Energy Agency. Traders said they were taking precautions to have alternative supplies in place if an embargo is implemented.

A spokesman at Saras SpA, one of Italy's largest refiners, said the company was "in routine talks with all our suppliers" regarding a possible need to replace Iranian crude.

The spokesman said 10% of the 75.3 million barrels it refined in the first nine months was crude oil from Iran. But, he added, "We don't anticipate any supply problems," and Saras won't reduce capacity in case of Iranian oil embargo.

An embargo would squeeze refining margins, the spokesman said. Refining margins have already been under pressure this year and even twice turned negative after Libyan oil disruptions pushed up the price refiners pay for their crude.

Officials at other leading European refiners declined to comment, or said it was too soon to comment on a possible ban.

In a note Wednesday, Fitch Ratings said "the likely increase in oil prices that would result from a ban would be felt by all oil refiners, not just those that are big customers for Iranian oil."