The South Korean customs agency said Monday it has confiscated some 4 tons of smuggled urea solution and is planning to distribute them to the market.

The Korea Customs Service (KCS) said it had caught a group of local importers Friday for attempting to bring in 416 10-kilogram containers of urea solution hidden in lawfully imported goods from China through the western port of Incheon.

The service said it was investigating those smugglers of urea solution, a key fluid used in diesel vehicles to cut emissions.

After consultation with related government agencies, the KCS said it will come up with ways to sell the confiscated urea solution to the market.

The customs office said it will strengthen its customs clearance procedures as part of efforts to prevent illegal imports of products.

The seizure comes as South Korea has been grappling with a shortage of urea solution and its surging prices in recent weeks due to China's tighter controls on exports of urea and other chemicals.

China's move stems from a power crisis caused by a coal supply shortage. Coal is the main feedstock in the production of urea. South Korea heavily relies on China for its supply of urea, as 97.6 percent of its imports came from China in the first nine months of this year. (Yonhap)