In order to prevent children from being forcibly taken to another country by a parent in an international marriage, Japan should sign an accord to provide a legal framework for settling international child custody cases, a U.S. State Department official said Thursday in Tokyo.

Mary Ryan, assistant secretary for consular affairs at the State Department, said 55 countries have become signatories to the 1980 Hague Convention on the Civil Aspects of International Child Abduction. Japan is the only country in the Group of Seven leading industrialized nations that has not signed it.

Of the 75 countries that have not signed the convention, there have been 33 alleged cases of such child abductions involving Japan — the second-largest after the Philippines, Ryan said at the U.S. Embassy in Tokyo.

Just this week, Ryan said, a father from the United States “kidnapped” his 4- and 7-year-old children from his former Japanese wife and took them to the U.S.

Ryan said since parental abduction is not a crime in Japan, there is nothing the mother can legally do to get her children back. But if Japan were a signatory to the Hague Convention, it would give a legal framework for authorities to bring the case to court, she said.

“If this case came to an American court under the Hague Convention, I believe that the American court would decide in favor of the Japanese mother and return the children to Japan, where they have always lived.”

Under the convention, children caught in custody disputes are normally returned to the place where they have habitually resided. A court in the country where kidnapped children are taken would settle the case.

Ryan said Japan has been reluctant to sign the agreement out of fear that U.S. courts would routinely favor parents from the U.S.

However, she said, since 1995 more than 700 children who are American citizens were returned to foreign countries where they have lived with the other parent.

“I think that is a very good track record for American courts, which shows that it is not just a subjective decision based on a nationality.” Ryan said, “It is a decision of what is best for a child, and that’s what we are trying to get at in this convention.

“International parental kidnapping is traumatic to children and potentially dangerous . . . and the Hague Convention is the best tool available to combat it.”

The number of Japanese who marry foreigners in Japan has doubled over the past 10 years to more than 28,000 each year. The number of such marriages ending in divorce reached nearly 10,000 in 1997, up about 20 percent over five years.