US ambassador to South Korea Mark Lippert suffers nerve damage and needs 80 stitches after Seoul knife attack

Assailant shouted a 'pro-unification slogan' and slashed at the diplomat's face. He was forced to defend himself from his seat at a breakfast meeting before security officials intervened

U.S. Ambassador to South Korea Mark Lippert leaves a lecture hall for hospital in Seoul, South Korea, Thursday, March 5, 2015 after being attacked (AP)

The US ambassador to South Korea has undergone two and a half hours of surgery and received 80 stitches to his face after being targeted in a knife attack by a militant Korean nationalist.

Mark Lippert was attacked during a breakfast meeting at a performing arts centre in Seoul on Thursday morning, and doctors said he was left with an 11cm (4-inch) gash on the side of his face by an assailant using a small fruit knife.

Since the attack, which took place at around 7.40am local time (10.40pm GMT), Mr Lippert has received a phone call from President Barack Obama wishing him a quick recovery.

Doctors said his condition was stable after undergoing “very successful” surgery, and that the cut to his wrist had caused nerve damage that was repaired. He is expected to stay in hospital for three to four days.

The US ambassador to South Korea Mark Lippert (R) leaves a meeting after he was slashed in the face by a knife-wielding assailant (Reuters)

The assailant, identified as a 55-year-old activist called Kim Ki-jong, was known to police and has a history of militant activism. In 2010 he was given a suspended jail term for throwing a piece of concrete at the Japanese ambassador in Seoul.

Dressed in traditional Korean clothing, he reportedly shouted that “South and North Korea should be reunified” and that he opposed US-South Korean “war exercises” before lunging at Mr Lippert.

“The guy comes in ... He yells something, goes up to the ambassador and slashes him in the face,” witness Michael Lammbrau of the Arirang Institute thinktank told the Reuters news agency.

Blood stains from the US ambassador are seen on a table following his evacuation (Reuters)

“It sounded like he was anti-American, anti-imperialist, that kind of stuff,” he said.

“The ambassador fought him from his seat ... There was a trail of blood behind him,” Lammbrau said.

South Korean President Park Geun-hye, speaking in the United Arab Emirates, called it an “attack on the South Korea-US alliance”, while the US State Department said it “strongly condemns this act of violence”.

The US ambassador was slashed in the face by an assailant who was known to police as a militant activist campaigning for the unification of North and South Korea (Reuters)

Security personnel detain an assailant who attacked the US ambassador (Reuters)

Police said that while the assailant told them in custody that he had acted alone, he was known to be a member of the pro-unification group which hosted Thursday's event, the Korean Council for Reconciliation and Cooperation.

The group later issued a statement in which it condemned the attack and apologised to the governments of the US and South Korea.

The attack comes as the US and South Korea prepared for annual joint military exercises, which have been denounced by North Korea as preparations for war.

A spokesperson for the South Korean defence ministry said the drills, due to run for eight weeks, would continue as planned.

Additional reporting by agencies