U.S. Ambassador to South Korea Mark Lippert kept his upbeat tone in the hours after a shocking knife attack on him by a leftist activist during an event in Seoul on Thursday morning.

Lippert posted on his Twitter account after undergoing surgery that he was “doing well and in good spirits” and that he was “deeply moved by the support” he received from his acquaintances here. “Will be back ASAP (as soon as possible) to advance U.S.-ROK (South Korea) alliance!” he further wrote.

Even considering his position as an envoy to a key ally of his country, it would never be easy to send such a positive message soon after receiving 80 stitches on his face. This shows the depth of his commitment to enhancing the ties between South Korea and the U.S. and his affection toward people here.

Still, it is all the more regretful to see the ambassador suffering the injury as he has tried to get closer to ordinary citizens in the country from the bottom of his heart since he arrived here in October. We join all other Koreans in hoping for his prompt recovery and extending deep consolation to his family.

The attack on Lippert took place at a time when Seoul and Washington seemed in discord over some issues. U.S. Undersecretary of State Wendy Sherman came under fire here for her recent remarks that were interpreted by South Korean media as taking sides with Japan in rows over the history between the two countries. The U.S. also appeared displeased with South Korea’s hesitance to deploy an advanced missile defense system out of concern over China’s negative response.

The 55-year-old South Korean assailant may have misjudged his act would widen the rift between the two allies. He shouted slogans against the ongoing Seoul-Washington joint military drills after he was overpowered on the spot. A bloody attack on an envoy was the worst way of advocating peace. Many South Koreans might have felt like their hearts being slashed by his outrageous act.

It was also absurd for North Korea to hail his assault on Lippert as “deserved punishment.” The North may be the only state in the world that praises terror on a diplomat whose safety should be guaranteed in any circumstance under an international convention.

In a sense, the unprecedented assault on a U.S. ambassador may reveal the hysteric psyche of a dwindling pro-North Korean force here. Still, a thorough investigation should be made into it and strong measures should be taken to prevent such an incident from recurring.

The attack on Lippert may serve as an occasion to further deepen the alliance between South Korea and the U.S. if the two sides wisely cope with its aftermath. Lippert concluded his Twitter message with two Korean words meaning “go together.” We hope and believe when he is back to work, the youngest-ever U.S. ambassador here will be more determined to carry out his mission to cement the ties between the two countries. But it would be regretful not to see him walking his dog on Seoul streets anymore under tightened security.