South Korea's top tire manufacturer Hankook Tire Co. said Friday that its second-quarter operating income plunged 20 percent on-year, dragged down by unfavorable currency rates.

Operating profit stood at 201.1 billion won ($171.9 million) in the April-June period, compared with 251.2 billion won a year earlier, the company said in a regulatory filing.

Sales backtracked 2.5 percent to 1.6 trillion won over the cited period. Net profit figures were not disclosed.

Shares of Hankook Tire closed at 40,600 won on the Seoul bourse, unchanged from the previous session. The results were announced during the trading hours.

Hankook Tire said that the Korean won's strength against the euro, Japanese yen and other major currencies took a toll on its second-quarter performances. China's slowing growth was also cited as a contributing factor.

Hankook Tire forecast that sales are likely to expand in the United States, considering the 12 to 14 percent sales growth seen in the region in the second quarter. 

The world's No. 7 tire company also said it expects the premium tire business to bolster its performances down the road. (Yonhap)