South Korea has bought no Iranian crude oil for about three months after the reimposition of US sanctions on Tehran, a spokesman for Iran's Oil Ministry was quoted as saying on Sunday.

"For about three consecutive months, South Korea has had no oil imports from Iran," reported Shana quoting Kasra Nouri.

"South Korea is the first country to completely cut off oil imports from Iran following the unilateral US sanctions against Iran."

In May the United States pulled out of a 2015 deal between world powers and Iran under which sanctions were lifted in return for modification to its nuclear program.

Washington decided to reimpose sanctions and has told other countries they must halt all imports of Iranian oil from November 4 or face US financial measures.