South Korea's imports of Iranian crude oil more than doubled in the second quarter of the year from a year earlier following the lifting of international sanctions against the Middle East country, government data showed Wednesday.

A total of 25.35 million barrels of crude oil was imported from Iran during the April-June period, soaring 123.3 percent from 11.35 million barrels tallied over the same period last year, according to the data compiled by the Ministry of Trade, Industry and Energy.

Iran had been one of the biggest crude oil exporters to South Korea, which imports nearly all of its oil needs, until the international community imposed economic sanctions on it over its nuclear weapons program in 2012.

South Korea imported $9.36 billion worth of crude from Iran in 2011, but the number plunged to $2.27 billion in 2015, amounting to 42.4 million barrels.

As Washington and Tehran reached a landmark nuclear deal in January, South Korea sought to expand imports of Iranian oil, which is cheaper than that of other oil-rich countries.

With the sharp increase in Iranian crude, South Korea's overall oil imports increased 4.5 percent on-year to 266.38 million barrels during the three-month period.

Imports of oil-related products, such as liquefied petroleum gas, jumped 15 percent on-year to 77 million barrels in the second quarter on the back of low oil prices, while South Korea's production of refined oil grew 2.9 percent on-year to 282.9 million barrels.

South Korea's exports of petroleum products expanded 9.5 percent to 124 million barrels over the cited period, but the value of exports tumbled 23.6 percent on-year due to a low oil price trend. (Yonhap)