North Korean and Japanese negotiators have abruptly ended talks aimed at restoring diplomatic ties.
The original schedule had called for two full days of talks in Vietnam but the second day of discussions lasted less than an hour on Thursday.
A statement from Japan's foreign ministry said: "This round of working-group talks is over and we will continue to exchange views."
A session on Wednesday afternoon to discuss the sensitive issue of Pyongyang's abduction of Japanese citizens in the 1970s and 1980s was also cancelled.
Japan says it is impossible to form ties without resolving the issue of abductees, but North Korea is pushing to settle issues that stem from Japan's harsh colonial rule over the Korean peninsula between 1910 and 1945.
"The two sides stated each other's position on the abduction issue and normalisation of diplomatic relations, including settlement of the past," the statement said.
The talks in Hanoi are part of a six-country deal last month to halt North Korea's nuclear weapons programme in exchange for aid and diplomatic recognition.
Early this week, North Korea sent its chief nuclear negotiator to the US for talks and a delegation to meet Japanese counterparts.
Thorny issues
North Korea admitted in 2002 that its agents had abducted 13 Japanese to train Pyongyang spies in Japanese culture and language, sparking outrage in Japan.
Also on Thursday, state news agency Kyodo said Shinzo Abe, Japan's prime minister, was considering a new study of the government's role in forcing women, many of them Koreans, to act as sex slaves for Japanese soldiers during the second world war.
Abe's refusal to apologise again has angered Koreans and other Asians although he has also said that Japan stands by a 1993 apology acknowledging coercion.
At the UN on Wednesday, North Korea's envoy accused Japan of creating "a horrific atmosphere of terror" for Pyongyang sympathisers in Japan by probing into their activities following the North's nuclear and missile tests last year.
Western, Asian and developing nations on the board of the Vienna-based UN International Atomic Energy Agency urged North Korea to honour the deal towards denuclearisation.