The head of Korea's Olympic squad, Lee Ki-heung, said Tuesday that it is getting "extremely tough" for the country to achieve its gold medal target after key athletes were either knocked out early on or disqualified by dubious calls.

Swimmer Park Tae-hwan, judoka Cho Jun-ho and fencer Shin Ah-ram became targets of dubious decisions by referees over the last three days.

As of Monday, Korea won two gold, two silver and two bronze medals. "If things had gone as planned, we should have had at least three or four gold medals by now," Lee said. Korea could have grabbed four gold medals on the first day of the Olympics, but won only one, for the men's 10-m air pistol event. The female archery team added another gold later.

The men's archery team, considered a favorite, ended up winning bronze, and Park, who was aiming for a new world record and one gold, had to be satisfied with silver as he lost his stride after being disqualified from the final of his signature 400-m freestyle race before the decision was overturned.

But the Korean team plans to push ahead with its target of winning at least 10 gold medals and ranking within the top 10 overall. It is now banking on its stable of underdogs.

It is going for at least two gold in Taekwondo, one in gymnastics (Yang Hak-seon, men's vault), and another in badminton (men's doubles, Jung Jae-sung and Lee Yong-dae). It also hopes to win more medals in judo and archery after one gold for judoka Kim Jae-bum on Tuesday and the gold won by the women's archery team.

Other sports being watched are boxing (Shin Jong-hoon) and wrestling. Korean athletes have traditionally done well in both, but their performance has not been stellar at international events like the Olympics. Korea has not won a gold medal in boxing since the 1988 Seoul Olympics, and failed to grab gold in wrestling in Beijing in 2008 and at the 2010 Asian Games in Guangzhou.

"Morale is still high among the Korean athletes," Lee said. "Although we've experienced some unfortunate events, we're still holding up."

"As long as Korean athletes continue to show their strong spirit, we will be able to achieve our goal," he added.