U.S. ambassador to South Korea Mark Lippert was slashed in the face by a Korean nationalist but was not seriously hurt during an attack at a breakfast forum held in the capital on Thursday to discuss Korean reunification, police and witnesses said.
Lippert, 42, was bleeding from a facial wound but was walking after the attack as he was taken to the hospital. He was later reported to be in stable condition and officials in Washington said his injuries were not life-threatening.
"We strongly condemn this act of violence," U.S. State Department spokeswoman Marie Harf said.
U.S. President Barack Obama quickly called Lippert to wish him a speedy recovery, a White House official said.
The assailant was caught by police and identified as 55-year-old Kim Ki-jong. Witnesses and police said he used a small fruit knife in the attack.
In 2010, Kim tried to attack the Japanese ambassador to Seoul by throwing a piece of concrete and was given a suspended jail term, according to police.
Kim was dressed in traditional Korean clothing and shouted that North and South Korea should be reunited just before he attacked Lippert. He also shouted that he opposed "war exercises", an apparent reference to annual joint U.S.-South Korean military exercises that began this week.
"The guy comes in wearing traditional Korean brown and tan dress. He yells something, goes up to the ambassador and slashes him in the face," witness Michael Lammbrau of the Arirang Institute think tank told Reuters.
Kim is a member of the pro-Korean unification group that hosted the event, according to police. He also stages one-man protests against Japan over disputed islands known as Dokdo in Korean and Takeshima in Japanese.
"People wrestled the guy to the ground, the ambassador was still in his chair. The ambassador fought him from his seat ... There was a trail of blood behind him. He had about a seven inch-long gash on the right side of his face," Lammbrau said.
Lammbrau said the man shouted about Korean independence while he was being restrained. "It sounded like he was anti-American, anti-imperialist, that kind of stuff."
Lippert, who took office in November, is known for an open, informal style. He is active on Twitter and can often be seen walking his basset hound, Grigsby, in Seoul. His wife recently gave birth to a son, who was given a Korean middle name.
Thursday's event was hosted by the Korean Council for Reconciliation and Cooperation. The group later issued a statement in which it condemned the attack and apologized to the governments of the United States and South Korea.
Police were at the venue as part of routine operations but not at the request of the U.S. embassy or the organizer, according to a police official.
The annual U.S.-South Korean military exercises routinely provoke an angry response from North Korea, which denounces them as a preparation for war.