The US ambassador to South Korea was knifed early Thursday by an activist shouting pro-unification slogans, officials and news reports said.

Mark Lippert was hospitalized with injuries to his right cheek and left wrist, as well as cuts to his arm and fingers, Yonhap News Report said, citing unnamed officials.

His injuries were not life-threatening, the US State Department said. “We strongly condemn this act of violence,” it said. “Embassy Seoul is coordinating with local law enforcement authorities.”

Suspected attacker Kim Ki Jong reportedly walked up behind Lippert before he was due to give a speech at a breakfast meeting, pushed him on to the table and assaulted him with a paring knife, Yonhap reported. Earlier reports had said a razor was used.

Wearing traditional Korean dress, he shouted “The two Koreas must be reunified” before knifing the ambassador, Chosun Ilbo reported.

Kim, 55, also shouted his opposition to joint US-South Korean military exercises that started Monday, saying they antagonized North Korea, as he was dragged to a police car by officers, Yonhap reported.

The activist on Tuesday wrote in a blog post that the annual Key Resolve and Foal Eagle exercises were “the reason why the reunion between family members couldn’t take place.”

Prime Minister Lee Wan Koo called the attack on the ambassador “regrettable.”

Kim is a member of a South Korean group that favours reunification with North Korea, radio broadcaster KBS reported.

He was reportedly handed a suspended sentence in 2010 for throwing pieces of concrete at Japan’s then ambassador.

Kim heads an organization that campaigns against Japan’s claim to the South Korean-administrated Dokdo Islands. He changed the address of is family register to the remote islands in 2006, Kyodo said.

Thursday’s breakfast event was hosted by the Korean Council for Reconciliation and Cooperation, China Daily reported.

South Korean authorities said they would increase security for US facilities and personnel, Yonhap reported.

Lippert, 42, has been the US envoy in South Korea since October. News reports said he was known for his light use of security, frequently seen walking his dog in the capital. He reportedly gave his son, born in the country, a Korean middle name. SAPA