Dubai: Iran’s oil minister said foreign oil companies that owe his country billions of dollars are likely to settle their debts in euros.

Greece’s Hellenic Petroleum, Italy’s Saras and Royal Dutch Shell owe Iran about $4 billion which will be paid back in euros, Iranian Oil Minister Bijan Zanganeh was cited by the ministry’s news agency Shana as saying on Tuesday.

Shell has said it was ready to settle its debts to Iran, but Greece’s Hellenic Petroleum is having trouble to pay Iran back and “alternative methods are being worked out”, Zanganeh said, according to Shana. He did not elaborate.

A Shell spokesman said: “We will settle our outstanding debt to NIOC (National Iranian Oil Co) as soon as we are lawfully able to do so,” declining to comment on whether the payment would be made in euros.

Zanganeh also said Emirates National Oil Co, Japan and the Netherlands had started settling their debts to Iran’s central bank.

Iran wants to recover tens of billions of dollars it is owed by buyers of its oil in euros and is billing new crude sales in euros, too, looking to reduce its dependence on the US dollar following last month’s sanctions relief.

A source at state-owned NIOC told Reuters last week that Iran will charge in euros for its recently signed oil contracts with firms including French oil and gas major Total, Spanish refiner Cepsa and Litasco, the trading arm of Russia’s Lukoil.

Safar-Ali Karamati, deputy director of international affairs for marketing and crude oil operations at NIOC, has told Shana that Iran favours the euro as the payment currency for its oil export contracts.