The six victims of the flash flood included a child
North Korea has expressed regret for unleashing dam water that drowned six campers downstream in the South, officials say.
The reported statement came during talks between the two Koreas aimed at preventing flooding on the Imjin River which spans their militarised border.
A South Korean official said they considered the statement "an apology".
The talks went ahead despite short-range missile tests by North Korea off its east coast on Monday.
Wednesday's meeting in the North Korean border town of Kaesong was requested by Seoul after the unexpected opening of the dam caused a deadly flash flood last month.
"North Korea has expressed regret that there were unexpected human casualties in the South as a result of the Imjin River incident and expressed condolences to the families," a South Korean Unification Ministry official told reporters.
"The government considers the position expressed by the North as an apology."
The North said it had to discharge the water to avoid a bigger catastrophe, but did not elaborate on what the danger was, the official said.
Pyongyang has built several dams on the river including one a few kilometres north of the heavily armed border.
Ties between North and South Korea have been frosty since South Korean President Lee Myung-bak linked progress in the North's dismantling of its nuclear programmes to aid deliveries.
However, in recent months the North has appeared willing to tackle humanitarian issues, and discuss their joint running of the Kaesong industrial plant.