Economic talks between the two Koreas remain stalled for a second day in a standoff over North Korea's nuclear weapons. South Korean economic aid to the North may be in jeopardy.
South Korean reporters in Pyongyang describe Wednesday's economic talks between the two Koreas as a "war of nerves."
For a second straight day, North Korea refused to discuss its nuclear weapons programs, insisting that the talks focus on the transfer of food and money from Seoul.
But South Korea's chief delegate said he cannot simply pass over remarks made Tuesday by his northern counterpart. North Korea warned of "an unspeakable disaster" if the South confronts the North over its nuclear ambitions.
Official North Korean media repeated the threat on Wednesday. It calls South Korea's recent display of unity with the United States "a very dangerous move to increase the danger of nuclear war."
South Korean delegates said Wednesday threats like that could jeopardize inter-Korean economic projects.
A South Korean opposition party is demanding that Seoul end the talks early. The Unification Ministry in Seoul says it will not do that unless North Korea makes further threats.
But the ministry is demanding an apology for North Korea's recent statements, or at least an explanation.
In a separate controversy, a group of ethnic Koreans living in Japan is denying reports it helped smuggle missile components to North Korea.
A defector who says he used to be a North Korean missile scientist made the accusation Tuesday before a hearing of U.S. lawmakers in Washington.
The group he named, the General Association of Korean Residents in Japan, does have ties to Pyongyang. Its members make ferry trips to North Korea carrying boxes of food, money and other goods.
The group calls the testimony a "fabrication" and a "blatant political charade."
Japan's Chief Cabinet Secretary Yasuo Fukuda said if the allegations prove true, Japan may have to respond. He did not go into detail about what that response would be, but the incident may lend support to the ruling conservative party's call for economic sanctions against Pyongyang.