North Korea said Friday that South Korea is the first to blame for the death of a fisheries official killed at sea last month because the South failed to exercise proper control over its citizen.

But the North also said such an "accidental" incident should not lead inter-Korean relations to a "catastrophe." It also said it tried its best, unsuccessfully, to search for the body of the South Korean official to return it to his family.

The 47-year-old fisheries official was fatally shot by the North's military while adrift in the North Korean side of the Yellow Sea, according to the South's military. He went missing the previous day while on duty near the western border island of Yeonpyeong.

"Explicitly speaking, the recent inglorious incident in the waters of the West Sea of Korea was the result of improper control of the citizen by the South side in the sensitive hotspot area at a time when there are tension and danger due to the vicious virus sweeping the whole of South Korea," the Korean Central News Agency (KCNA) said.

"Therefore, the blame for the incident first rests with the South side," the KCNA said.

North Korea also tried its best to retrieve the body of the official to "no avail," it added.

"We are regretful for this and have decided to take sustained necessary measures in the future, too, in the relevant field," it said, without further explanation of the measures.

The North also said it "does not want to see the repetition of any unpleasant precedents in which accidental incidents led the north-south relations to a catastrophe."

South Korea called for swift efforts for a joint probe into the killing.

"We call for the inter-Korean military hotlines to be reconnected first for communication between the two Koreas," Cho Hey-sil, deputy spokesperson of the unification ministry, said at a regular press briefing.

The North accused South Korea's main opposition People Power Party of using the incident as an opportunity for "attaining their dirty political purposes" and slandering the communist nation by raising the issue of human rights.

"The conservative forces allegedly valuing 'human rights' with great concern for it kept mum about ... the opening of indiscriminate machine gunfire into another citizen of its side when he was swimming across a river in the area along the Military Demarcation Line to enter the DPRK that killed him," the KCNA said, referring to North Korea by its official name.

The agency appears to be referring to an incident in 2013 when South Korean troops at the border shot and killed a man trying to swim across the Imjin River to defect to the North.

Last week, Tomas Ojea Quintana, the UN special rapporteur on North Korea's human rights situation, raised the issue during a meeting of the UN General Assembly and denounced the North's killing of the official. Earlier this month, he also urged Pyongyang to punish those responsible for the killing and to compensate the official's family.

Shortly after the incident in September, North Korean leader Kim Jong-un offered an unusually quick apology, saying that he feels "very sorry" for greatly "disappointing" President Moon Jae-in and other South Koreans with the "unsavory" incident.

The two Koreas, however, remain far apart on what happened during the incident, including whether the official's body was set on fire. Pyongyang remains unresponsive to Seoul's calls for a joint probe.

Inter-Korean relations have remained stalled since the no-deal summit between Kim and US President Donald Trump early last year.

The relations chilled further recently after the North blew up a joint liaison office in its border town of Kaesong and cut off cross-border communication in protest of the sending of anti-Pyongyang leaflets by activists in the South. (Yonhap)