Both South Koreans in the action, Kim Tae-hun in the men's and Sim Jae-young in the women's, made it to the semifinals.

Kim, who is chasing his third consecutive title in the men's under-54kg, cruised through the early stages with relative ease.

Kim beat Kitso True Molaodi of Botswana in the round of 64 by 15-2, and then knocked out Ryuta Matsui of Japan in the next round by 29-3. Kim then beat Hassan Haider of Britain 28-3 to reach the quarterfinals.

Against Deniz Dagdelen of Turkey in the quarters, Kim opened up an 11-1 lead in the first of three two-minute rounds. Dagdelen cut it to within 11-5 early in the third round, but Kim promptly picked up two points with a valid kick and went on to win by 27-7.

Sim defeated Fadia Farhani of Tunisia 15-5 in the quarterfinals, after dispatching Anargul Sabyr of Kazakhstan in the round of 32 and then Shyu Nai-Yun of Chinese Taipei in the round of 16.

Also in the same class, Dina Pouryounes Langeroudi, the first refugee athlete competing at a WTF world championships, was knocked out in the round of 32, losing to Andrea Ramirez Vargas of Colombia 6-2.

The opening ceremony was held later Saturday, with South Korean President Moon Jae-in giving a congratulatory speech and the North Korea-led International Taekwondo Federation staging a performance in the finale.

Moon spoke of the power of sports to foster peace as he welcomed the North Korean delegation in the first instance of inter-Korean sports exchange since Moon took office in early May.

"Friendship and goodwill exchanges between the two federations will of course greatly contribute to reconciliation between South and North Korea, as well as the establishment of peace on the Korean Peninsula," he added.

Moon then joined others in watching the historic performance by the ITF demonstrators. It was the first ITF performance at a WTF event held in South Korea. The two Koreas technically remain at war as the 1950-53 Korean War ended only with an armistice, not a peace treaty.

International Olympic Committee President Thomas Bach, who will be here for the closing ceremony next Friday, delivered a message through IOC Vice President Yu Zaiqing. Bach called this competition "a special moment for all athletes and fans" as the world championships have returned to the birthplace of the sport.

This is the 23rd edition of the WTF's signature tournament and seventh to take place in South Korea, the birthplace of taekwondo.

It's the largest world championships ever, with 971 athletes and 796 officials from 183 nations. The 2009 event in Copenhagen had previously been the largest with 928 athletes from 142 nations. The WTF said 17 countries, including Togo, Tanzania and Malawi, are competing for the first time.

All eight gold medalists from last year's Rio de Janeiro Summer Olympics are here. (Yonhap)