By Chris Hogg
BBC News, Tokyo
Japan's foreign minister says North Korea must let international inspectors resume monitoring of its nuclear sites.
Taro Aso also said the North would be pressed over its kidnapping of Japanese civilians in the 1970s and 80s, during six-nation nuclear talks next week.
Japan has made clear what it regards as the minimum acceptable outcome of the talks, which are set to resume on Monday after being stalled for a year.
Mr Aso wants inspections of the North's sites by the UN's nuclear watchdog.
Could there be any way other than inspections to verify any claim by North Korea that it had abandoned or suspended its nuclear programme, he asked.
"Without it, we cannot believe a story North Korea would tell us, that it stopped its nuclear facilities," he said.
North Korea and Japan share a mutual distrust.
The North has repeatedly demanded that Japan be excluded from the talks, but the United States regards Japan as an important part of the process.
Any final settlement that offered substantial aid to North Korea in return for abandoning its nuclear programme would require financial support from Tokyo.
Mr Aso also said that Japan wants to hold bilateral talks with North Korea to discuss the restoration of normal relations between the two countries.
He also wants discussions on the North's past abductions of Japanese nationals and its missile development programmes.
The two countries last held talks on these issues in February.