The 28-year-old Kyoto Sanga player, who only returned to the squad last November following a lengthy lay-off with a similar injury, twisted knee ligaments during a challenge in the first half and was carried off on a stretcher.

Coach Huh Jung-moo is set to call up either Suwon Bluewings defender Kang Min-soo or Hwang Jae-won of Asian champions Pohang Steelers to take Kwak's place in his 23-man World Cup squad.

"Kwak will need at least four weeks to recover from twisting a ligament in his left knee," said media officer Lee Won-jae.

South Korea complete their preparations against European champions Spain on Thursday ahead of their opening game against Greece in Group B on June 12.