Video: Ambassador slashed in South Korea

The U.S. Ambassador to South Korea, Mark Lippert, was attacked in Seoul, and is in stable condition, receiving treatment at a local hospital, according to the U.S. embassy.

According to Seoul police, Lippert was slashed on his right cheek and hand with a knife measuring about 10 inches long at 5:42 p.m. ET on Wednesday.

A South Korean news agency reported that the suspect was opposed to the joint South Korea-U.S. military drills that launched earlier this week, but Seoul police said the motive for the attack and how it was organized are under investigation.

State Department spokeswoman Marie Harf confirmed the ambassador had been attacked while giving a speech in Seoul Thursday morning, and said that the South Korean embassy is coordinating with local law enforcement on the attack.

"We strongly condemn this act of violence. The ambassador is being treated at a local hospital. His injuries are not life threatening," she said.

South Korean president, Park Geun-hye condemned the attack: "This incident is not only a physical attack on the U.S. ambassador, but an attack on the South Korea-U.S. alliance and it can never be tolerated."

She pledged a "thorough investigation and strengthening" of protection.

Lippert is a longtime friend and confidant of President Barack Obama, who has been a member of his inner circle since the President's time as senator. According to National Security Council spokeswoman Bernadette Meehan, Obama called Lippert to wish him well.

"The President called U.S. Ambassador to the Republic of Korea, Mark Lippert, to tell him that he and his wife Robyn are in his thoughts and prayers, and to wish him the very best for a speedy recovery," Meehan said in a statement.