A vast oil field containing an estimated 53 billion barrels of crude oil has been discovered in Iran, President Hassan Rouhani announced Sunday, a find that could boost the country's battered economy amid stringent US sanctions.

The oil field in southwest Iran stretches over an area of 2,400 sq km (about 1,491 square miles) in the Khuzestan province and is around 80 meters (262 feet) deep, according to the Iranian leader.

It would be the country's second largest oil field, behind one in Ahvaz containing an estimated 65 billion barrels.

"We have discovered a new big oil field with 53 billion barrels of reserves," Rouhani said in a speech Sunday in the city of Yazd, according to the semi-official Mehr news agency.

"This is a small gift by the government to the people of Iran," he added, according to Agence France-Presse (AFP).

Iran, which is a founding member of the Organization of the Petroleum Exporting Countries (OPEC), currently has estimated proven crude oil reserves of 155.6 billion barrels, according to energy giant BP. The new discoveries would add about 34% to its total reserves.