SEOUL, South Korea (AP) — A Seoul court on Friday handed a 12-year prison sentence to a South Korean man who slashed and seriously injured the U.S. ambassador during a March forum.

Kim Ki-jong was convicted of attempted murder, assaulting a foreign envoy and obstruction, according to Seoul Central District Court spokesman Joon Young Maeng.

Both Kim and the prosecution have one week to determine whether to appeal, Maeng said. Prosecutors had previously asked for a 15-year prison term.

Kim slashed Mark Lippert during a breakfast forum in Seoul, leaving deep gashes on the envoy's face and arm. Lippert was treated for five days at a Seoul hospital.

Kim has described himself as an anti-U.S. activist. He told police that his assault was meant to protest annual U.S.-South Korean military drills but that he did not intend to kill the ambassador.

The drills, which are meant as a deterrent against North Korean attack, are a major source of friction on the Korean Peninsula. Pyongyang says they are practice for a northward invasion to topple the dictatorship that has ruled the country since its founding in 1948. U.S. and South Korean officials say the drills are defensive in nature.

Police said Kim attempted to kill Lippert because he knifed him more than twice with a force that was enough to penetrate the ambassador's arm as he tried to block the attack.

During earlier police questioning, Kim also said South Korea is a semi-colony of the U.S. and that North Korea has an independent, self-reliant government, according to Seoul police. Shortly after his arrest, Kim shouted that the U.S.-South Korea war games were an obstacle against a Korean unification.

The Korean Peninsula remains in a technical state of war since the 1950-53 Korean War ended with an armistice, not a peace treaty. About 28,500 American soldiers are deployed in South Korea to deter potential aggression from North Korea.