The US ambassador to South Korea,was slashed on his face and arm in Seoul on Thursday by a lone, blade-wielding activist opposed to ongoing US-Korean military drills.

The US ambassador to South Korea,was slashed on his face and arm in Seoul on Thursday by a lone, blade-wielding activist opposed to ongoing US-Korean military drills.

Witnesses described how a man with a blade concealed in his right hand had lunged across a table at Mark Lippert at a breakfast function at the Sejong Cultural Institute in central Seoul.

The assailant, dressed in traditional Korean clothes and identified as Kim Ki-Jong, 55, was immediately wrestled to the ground and taken into police custody.

As he assaulted Lippert, Kim screamed a slogan in favor of reunifying the divided Korean peninsula, and later shouted his opposition to joint US-S.Korea military exercises that began on Monday.

Kim was known to police having been handed a two-year suspended sentence in 2010 for throwing a rock at the then Japanese ambassador to Seoul.

Video footage showed the ambassador being rushed out of the building holding one hand to his bleeding right cheek, and his other hand smeared with blood with an apparent wound to the wrist.

The 42-year-old envoy was bundled into a police car and taken to a nearby hospital, where he was initially treated before being transferred to the prestigious Severance Hospital.

The US State Department confirmed Lippert's injuries were not life-threatening and said it "strongly condemned this act of violence".

The White House said President Barack Obama had called the ambassador, wishing him a speedy recovery".

Lippert was part of Obama's inner circle during the then senator's rise to the White House.

He took on senior roles in national security and defense after the 2008 presidential campaign, before becoming ambassador to Seoul in October last year.