TOKYO (AP) -- Japan's government is looking into re-opening official talks with North Korea to resolve questions over the abductions of Japanese citizens decades ago, raising concerns among allies who fear Tokyo's focus on that issue might weaken efforts to rein in Pyongyang's nuclear weapons program.

Chief Cabinet spokesman Yoshihide Suga said Wednesday that high-level talks with the North are possible if they would lead to a breakthrough on the abductions. Prime Minister Shinzo Abe has indicated he is open to holding a summit with North Korean leader Kim Jong Un if such a breakthrough could be made.

Abe dispatched a senior adviser to Pyongyang last week, catching Seoul and Washington off guard. Both said they were not given prior notice.

Washington and North Korea's neighbors have been stepping up their pressure on Pyongyang since it conducted a rocket launch and its third nuclear test earlier this year.

Though Tokyo is also deeply concerned by North Korea's development of nuclear weapons and long-range missiles, the abductions have long been at the top of its agenda and are the biggest obstacle to resuming official talks, which have been stalled since last November.

But Glyn Davies, the U.S. special representative for North Korea policy, warned North Korea might be trying to use talks with Japan to drive a wedge between the policies of Tokyo, Washington and Seoul.

Details of the Japanese envoy's talks in Pyongyang have not been disclosed, but Abe said this week that Japan must take the lead in resolving the abduction issue.

After years of denying allegations that its agents kidnapped more than a dozen Japanese in the 1970s and `80s, North Korea made an about-face in 2002 and after a summit meeting in Pyongyang with then Prime Minister Junichiro Koizumi allowed five of the abduction victims to return to Japan. It said the others were either dead or had not been abducted to begin with.

Though at first seen in Japan as a major step forward, questions soon began to emerge over whether the North had really come clean. Japanese officials now say they believe there could be many more Japanese abductees still alive in the North. Japan is demanding further information and the prompt release of any living abductees.