Tensions now escalate on Korean Peninsula after apparent defector killed by North Korea

Days after North Korea leader Kim Jong Un apologized for his troops killing a South Korean official adrift in North Korean waters, tensions escalated with South Korea for allegedly "intruding" into the disputed sea border in search of the body.

Kim Jong Un issued a rare apology Friday over the killing of a South Korean official who was apparently trying to defect to North Korea, saying he was "very sorry."

Troops fatally shot the public servant who began to flee after refusing to answer questions. The object in North Korean waters on which the official was trying to escape was burned, and the body was not recovered.

On Sunday, ships from South Korea arrived in the disputed waters to search for the missing body, prompting North Korea to accuse its neighboring, rival country of intrusion. 

"We urge the South side to immediately halt the intrusion across the military demarcation line in the West Sea that may lead to escalation of tensions," the official Korean Central News Agency said. "It arouses our due vigilance as it may lead to another awful incident." 

South Korean President Moon Jae-in is under sharp criticism from some political groups in the country for not rescuing the man in time. He gave his condolences to the grieving family and apologized Monday saying the government failed its responsibilities to protect citizens.