The European Union, which is poised to slap sanctions on dozens of Iranian companies and individuals, remains split over targeting the country's oil sector, diplomatic sources said Wednesday.

With Spain, Greece and Italy significantly dependent on oil from Iran, "there will be no oil sanctions against Tehran" announced at talks Thursday between the EU's 27 foreign ministers, an EU diplomat said.

The ministers are expected to agree an assets freeze and travel ban on an extra 143 Iranian companies and 37 people while calling for a resumption of global talks on Iran's contested nuclear programme.

"France, Germany and Britain are in favour of oil sanctions," said another diplomatic source "but there is no agreement between the 27".

"Oil imports is quite often a national interest of great importance because some member states do import a lot of oil from Iran," said the source.

EU data shows oil imports of crude oil from Iran in 2010 amounting to 5.8 percent of total EU imports, making the country the fifth supplier at the time after Russia, Norway, Libya and Saudi Arabaia.

Of that total, Spain accounted for 14.6 percent, Greece for 14 and Italy for 13.1 percent.

EU diplomats said cash-strapped Greece led opposition to an oil embargo, with one source adding: "Iran sells them on credit which is a considerable advantage in these times."