US Ambassador Mark Lippert attends a press conference upon his release from a Seoul hospital after five days of treatment of injuries caused by a knife attack, March 10, 2014.[Photo/IC]

Lippert declined to comment on potential changes to his security arrangements. He said he expects to return to work as soon as possible and to make a full recovery.

"I feel pretty darn good, all things considered. I mean it was obviously a scary incident. But I'm walking, talking, holding my baby, hugging my wife, so I just feel really good," Lippert said.

Kim was given a suspended jail sentence in 2010 for trying to attack the Japanese ambassador by throwing a piece of concrete. He said after he attacked Lippert he was protesting against annual joint US-South Korean military drills, which began last week.

Lippert was accompanied by his bodyguard, an unarmed South Korean policeman, when the attack took place at a government-owned theatre across the street from the heavily guarded US embassy. Other police were present at the event, although not at the request of the US embassy or organisers.