U.S. accusations that North Korea was behind the cyberattack on Sony Pictures could force Japan to choose between backing its ally Washington and keeping talks on track with Pyongyang about Japanese citizens abducted decades ago.
Washington is weighing how to punish North Korea after the FBI concluded Pyongyang was responsible, including possibly returning North Korea to the U.S. list of state sponsors of terrorism. North Korea has denied that it was to blame.
Japanese Chief Cabinet Secretary Yoshihide Suga strongly condemned the hacking on Monday but stuck to the line that Tokyo saw no direct impact on the talks over the fate of Japanese citizens abducted Pyongyang to help train spies.
Suga also did not directly link North Korea to the attack on Sony.
Japanese Prime Minister Shinzo Abe has made finding answers to the fate of the Japanese citizens abducted decades ago to help train North Korean spies a signature issue of his political career.
"The abduction issue ... forces Abe to make a decision whether to go along with the United States, even at the expense of antagonizing North Korea," said Sophia University professor Koichi Nakano.
Japan eased some sanctions on North Korea in July in return for the North reopening its probe into the status of the abduction victims. In October, North Korea told Japanese diplomats who traveled to Pyongyang that it would deepen its probe, but there was no sign of any imminent breakthrough.
The Sony hacking, however, could end up giving Abe a face-saving excuse to end the talks if they aren't yielding results.
"At the moment, he's in a really difficult spot," said Brad Glosserman, executive director of Pacific Forum CSIS. "But his line could be 'We want to keep talking but ... if you don't give me something, I'm going along with the Americans'."
Pyongyang admitted in 2002 to kidnapping 13 Japanese citizens decades before. Five abductees and their families later returned to Japan but Tokyo wants to know the fate of the remaining eight, who Pyongyang has said are dead, and others Japan believes were also kidnapped.
Japanese media have mostly treated the Sony hacking as a purely American affair despite the fact the Hollywood studio is a subsidiary of an iconic Japanese firm.
Accusing Pyongyang for the hack could also spark a backlash against ethnic Koreans in Japan. Many are descendents of those who came to Japan as laborers during Japan's 1910-1945 colonization of the Korean peninsula and were born in Japan, but are not automatically entitled to Japanese citizenship.
Long subject to discrimination, ethnic Koreans have become targets of "hate speech" demonstrations by nationalist groups.
(Additional reporting by Kiyoshi Takenaka and Tetsushi Kajimoto; Editing by Raju Gopalakrishnan)