The official told a televised interview on Saturday night that the rise in crude production from Iran's joint oilfields has increased its exports; the country's exports have soared by an average of 60,000 b/d since the beginning of the current Iranian calendar year which began on March 21.

"Iran is now exporting over 2.5 million barrels/day of crude oil and gas condensate," Zangeneh said.

He said the increase in crude oil production capacity and exports has taken place as it was planned, "but I am concerned about future years if not enough investment is made in the sector."

"What matters in the Organization of the Petroleum Exporting Countries (OPEC) is the number of produced crude oil barrels by the members; and we must increase our production capacity."

Iran's crude oil production capacity is less than 4 mbd currently, he said, adding plans are under way to bring the production capacity to 4.5 mbd or even beyond, if resources allow.