South Korea football coach Uli Stielike said Monday he isn't yet thinking about bringing in the country's young footballers to the senior national team, although they've been impressive at the ongoing FIFA U-20 World Cup.

Stielike said Lee Seung-woo and Paik Seung-ho, two FC Barcelona prospects who were pivotal for South Korea's qualification to the round of 16 of the U-20 World Cup, proved their talents in their age group, but they will have a tough time on the senior side.

"These players really performed well in the group stage of the U-20 World Cup," Stielike said at the National Football Center in Paju, north of Seoul, where the senior national team began training for the upcoming FIFA World Cup qualifier against Qatar. "But before the World Cup, they played against (South Korean pro club) Jeonbuk Hyundai Motors in a friendly match, and I saw there is still a gap between the U-20 level and the senior level. I think it's too early to call up the U-20 players to the national team."

South Korea's U-20 team lost 3-0 to Jeonbuk, the reigning Asian club football champions, last month in a friendly before the U-20 World Cup, which kicked off May 20.

"It's not easy for young footballers to compete at the senior level," Stielike added. "Just look at the status of our under-23 national team players last year and check how many are regular members with their clubs."

Stielike said the ongoing U-20 World Cup will give the senior national team players more energy as people are now paying more attention to football.

"It's very encouraging to us that people are showing their support for football," he said. "It's very nice to see many fans visiting football stadiums, and this is positive for us."

Stielike's side will face Qatar in their Group A qualifier in the final Asian qualifying round for the 2018 FIFA World Cup in Doha on June 13. Before the qualifier, they will meet Iraq in a tune-up on June 7 in the United Arab Emirates.

The German coach announced a 24-man squad last week, but only half of them, including Tottenham Hotspur attacker Son Heung-min and Swansea City anchorman Ki Sung-yueng, were able to attend the national team's first training session. The remaining 12 players were not able to join due to their club duties.

"With this number of players, it's difficult to do tactical training on the field," he said. "So for this week, we'll focus on improving each player's fitness and form."

The World Cup qualifier against Qatar will be staged during the Ramadan period. Stielike, however, said the fasting period for Muslims won't influence South Korean players.

"Qatar should be affected by Ramadan, not us," he said. "Qatar are a strong team at their home. They will fight until the end, so it's going to be a tough match for us."

With three matches remaining in Group A, South Korea are currently in second place, the last automatic qualification spot, with 13 points from four wins, one draw and two losses, four behind leaders Iran. Uzbekistan are right behind South Korea at 12 points.

Qatar are already eliminated from qualifying. They're last among six nations with four points.

Only the top two teams from each of the two groups advance straight to the World Cup finals, while the two third-place teams will have to go through the playoffs for the right to join the other four. (Yonhap)