France will stop buying Iranian oil on a "national basis" as part of its campaign to raise pressure on Tehran over its contested nuclear programme, the foreign ministry said Thursday.

Spokesman Bernard Valero gave no details of the measure, but the US Energy Information Agency estimates that France imports the equivalent of 49,000 barrels of Iranian crude per day, a tiny fraction of Iran's exports.

The French energy giant Total is still present in Iran, but only operates a joint venture with an Iranian lubricants firm, having halted its oil production and, in the middle of last year, stopped fuel sales there.

France has said it will work with its EU partners towards broader sanctions against Iran.