South Korea have been dealt a serious blow in the build-up to this summer's World Cup Finals in Germany after it was confirmed that striker Lee Dong-Gook has suffered a serious injury to his right knee.

The 26-year-old Pohang Steelers star requires surgery to repair torn cruciate ligaments in the knee.

Dong-Gook had been a regular in South Korea coach Dick Advocaat's starting line-up of late but the Dutchman will now have to look elsewhere for a regular goalscorer.

"Lee cannot take part in the World Cup in Germany because of his injury, which will require surgery and up to six months of treatment," said Pohang spokesman Shin Joo-Hyon.