The United States strongly condemned the “act of violence” which left the ambassador bleeding profusely as he was taken to hospital, and said that President Barack Obama had spoken with him.
“The President called (Lippert) to tell him that he and his wife Robyn are in his thoughts and prayers, and to wish him the very best for a speedy recovery,” said Bernadette Meehan, National Security Council spokeswoman.
Witnesses said a man with a blade concealed in his right hand attacked Lippert as he was attending a breakfast function at the Sejong Cultural Institute in central Seoul.
Video footage in the immediate aftermath of the attack 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.
Lippert, 42, was bundled into a police car and rushed to hospital, where a US embassy spokesman said he was in a “stable” condition.
State Department deputy spokeswoman Marie Harf said that Lippert’s injuries were not life threatening.
“We can confirm that (Lippert) was assaulted Thursday morning in Seoul while giving a speech. We strongly condemn this act of violence,” she said.
Kim Young-man, a spokesman for the Korea Council for Reconciliation and Cooperation which hosted the breakfast function, apologised for the lack of security at the event.
“This man suddenly jumped out of the audience seat when the breakfast was about to start at the table,” Kim told reporters.
“Other people tried to stop him but the situation unfolded too quickly. The ambassador was injured on the face and sent to hospital,” he said.
Security staff and police officers were later seen tackling the assailant, who was dressed in traditional Korean clothes and reportedly shouted an anti-war slogan as he lashed out at the envoy.
The United States and South Korea launched annual joint military exercises this week, triggering a surge in tensions with North Korea.
Nearly 30,000 US troops are permanently stationed in South Korea and the US would assume operational command in the event of an armed conflict with the North.
Some television reports said the attacker was known to police and had previously assaulted the Japanese ambassador to Seoul in 2010.
Lippert, a former US assistant secretary of defense for Asian affairs, took up his post in South Korea in October last year.
He was part of Obama’s inner circle during the then senator’s rise to the White House, and took on senior roles in national security and defence after the 2008 presidential campaign. -AFP