Iran is poised to export its first oil shipments to Europe since international economic sanctions were lifted in mid-January, the oil ministry's SHANA news service reported on Monday.
It said two million barrels of oil were being pumped aboard a tanker at Kharg Island in the Gulf, bound for French energy giant Total.
Another two tankers were preparing to ship a million barrels each to Spain's CEPSA and Lukoil of Russia, SHANA reported.
It cited oil terminals official Pirouz Moussavi as saying on Sunday that loading of the tankers would be complete within 24 hours.
"For the last four years, no oil has been shipped to Europe because of the unjust sanctions against our country," Moussavi added.
In early 2012, the European Union and United States strengthened economic sanctions against Iran because of its controversial nuclear programme, forcing the Islamic republic to halt oil exports to Europe.
Since then, Asia -- mainly India and China -- have been the main market for Iranian oil.
In recent years, Iranian oil exports have fallen from more than 2.2 million barrels per day to about one million bpd.
It currently produces 2.8 million bpd.
Iran's nuclear agreement last July with world powers means that now that most of the sanctions have been lifted it can resume oil exports to Europe.
Last month, the National Oil Company said it had ordered production to increase by 500,000 bpd -- a move Tehran had long planned once the nuclear deal with world powers took effect.
When President Hassan Rouhani visited France in January, a deal was signed with Total to buy 160,000 bpd.
Oil Minister Bijan Zanganeh said the contract with Total would take effect from February 16, SHANA said.
Oil prices rose on Monday with US benchmark West Texas Intermediate for March delivery climbing 57 cents to $33.01 per barrel from Friday's close.
Brent North Sea crude for delivery in April advanced 36 cents to $33.72 a barrel in midday London trade.