TOKYO - The U.S. ambassador to South Korea, Mark Lippert, on Tuesday vowed to continue his "open and friendly" style of diplomacy as he left a hospital five days after being slashed by a knife-wielding assailant.

The incident horrified South Koreans, who have rushed to reassure Lippert and the United States that they appreciate the strong alliance between the two countries.

Appearing at a news conference at the Seoul hospital where he was being treated, Lippert had a big bandage on his cheek over the four-inch wound that required 80 stitches and a brace on his left arm, which was cut during the attack.

"This incident has only strengthened our love and affection for this country and our belief in the unbreakable bond that exists between the United States and the Republic of Korea," he said, according to the Yonhap News Agency.

Lippert, 42, who previously held posts at the Pentagon and the National Security Council, said that since he arrived in Seoul in the fall, he and his staff "have felt embraced and welcomed by the Korean people."

"In return, we have made it our mission to be open and friendly. And that will not change," he said.

Lippert said he felt "pretty darn good, all things considered."

"I mean, it was obviously a scary incident," he said at Yonsei University's Severance Hospital amid heavy security. "But I'm walking, talking, holding my baby, hugging my wife, so I just feel really good."

Lippert was at a Seoul breakfast forum, where he was due to give a speech, when a man approached him and slashed him with a 10-inch kitchen knife Thursday. The man, Kim Ki Jong, 55, had a history of violence - he threw a piece of concrete at the Japanese ambassador to Seoul in 2010 - and is reportedly sympathetic to North Korea.

Witnesses said he yelled "No war! The two Koreas should be united!" as he attacked Lippert. Police are seeking to charge him with attempted murder.

North Korea said the slashing was "deserved punishment" for U.S. participation in ongoing annual military exercises with South Korea.

Since arriving in Seoul, Lippert has gone to great lengths to be an approachable ambassador and connect with ordinary South Koreans.

Unlike previous ambassadors, Lippert made a point of walking from his official residence to the U.S. Embassy about half a mile away, stopping to greet Koreans along the way.