By Chris Hogg
BBC News, Tokyo
Proposed legislation in Japan would require it to impose economic sanctions on North Korea unless it gives details on its abduction of Japanese citizens.
Relatives of the missing are putting pressure on Tokyo to find answers
Japan's ruling coalition submitted the bill on Friday, adding to existing powers to impose sanctions.
The measure is part of Japan's ongoing efforts to step up the pressure on North Korea on the abduction issue.
North Korea has admitted kidnapping 13 Japanese citizens in the 1970s and '80s to train its spies.
Five have been allowed to return. Japan has demanded proof of what happened to the others.
It is sceptical about North Korea's insistence that they are dead. It also believes more of its citizens may still be held by the government there.
'Act of war'
Pyongyang and Tokyo have no diplomatic ties, although there is some trade between the two countries.
This new bill would require the government to impose sanctions on North Korea unless it gets the answers it wants.
The punishments would include a ban on the docking of North Korean ships at Japanese ports, and stopping private individuals in Japan from sending money to Pyongyang.
Two years ago Japan passed a law setting out a range of similar measures that could be imposed. The new legislation is designed to strengthen that policy.
Japan has up to now stopped short of imposing sanctions, preferring instead to pursue the matter through occasional talks, but there has been little progress.
Pyongyang has always said any imposition of economic sanctions would be regarded as an act of war.