Mark Lippert, the United States' ambassador to South Korea, was slashed in the face with a razor during a lecture in a public forum early on Thursday morning in Seoul, the State Department announced.
The State Department said the injuries did not appear to be life threatening. Pictures released on South Korean media showed Lippert bleeding and covering his face.
"We strongly condemn this act of violence," State Department spokesperson Marie Harf said in a statement.
The man was apprehended and taken into custody after the attack, the Associated Press reported.
Secretary of State John Kerry said on Twitter that his thoughts were with Lippert.
According to the Associated Press, the attacker allegedly yelled that North and South Korea should be unified just before the attack.
Lippert was appointed ambassador last year after serving in several senior roles at the Defense Department, including chief of staff to former Defense Secretary Chuck Hagel. Before serving at the Defense department, Lippert served as a foreign policy adviser to Barack Obama in the Senate before becoming Deputy Assistant to the President and Chief of Staff for the National Security Council in 2009. He also served two years in the U.S. Navy and was deployed to Afghanistan.
Lippert's wife gave birth to a son in Korea in January, something that the ambassador marked on his Twitter feed.
This is a developing story and has been updated