China's Xinhua News Agency says the Chinese government has requested that North Korea sternly punish those responsible for shooting dead three Chinese nationals near the two countries' border.

The provincial government of Liaoning, where the incident occurred, issued a statement on Thursday asking North Korean authorities to thoroughly investigate the case and punish those responsible for the matter.

The North reportedly told China that an initial investigation showed the case was an "accident." North Korea expressed its condolences for the victims and their bereaved families as North Korean border guards shot and killed three Chinese suspected smugglers last week.

Xinhua reported that Pyongyang told Beijing that it will punish those responsible and vowed to prevent a recurrence.