Preliminary data from the South Korean Customs Administration showed that the country imported no Iranian oil in September for the first time in six years, ahead of US sanctions in November.
South Korea, the world's fifth-largest oil buyer, imported 10.8 million tons of crude last month, up from 12.3 million tonnes a year ago, according to the data.
The final data from the state-run Korean National Oil Company is expected to be published later this month.
