South Korea's foreign exchange authorities were spotted buying dollars to curb the won's strength on Friday, traders said. The authorities were seen buying dollars when the won was around 1,180 per dollar, they said. The won was quoted at 1,181.15/3.15 per dollar as of 0205 GMT, compared with Thursday's domestic close of 1,196.0. The local currency strengthened to as firm as 1,180.7, according to traders.