Japanese police authorities want to carefully examine a U.S. government report released Friday on the activities of Japanese crime syndicates, known as yakuza, in the United States, police officials said.

The report said yakuza pose a threat to the U.S., and Japanese police want to determine whether yakuza syndicates have started concentrating their operations there.

According to the officials, the first confirmed overseas yakuza activities were in Hawaii in the late 1970s. The Inagawa-kai syndicate was also verified to be investing in the U.S. via affiliated companies in the early 1990s.

Japan and U.S. investigative authorities have been on their guard for a possible shift in yakuza interests to the U.S. since Japan enacted the Anti-Organized Crime Law in 1992.

The Diet also has passed laws against organized crime syndicates in 1999 and this year.

Although the International Crime Threat Assessment report states that Inagawa-kai investment in U.S. real estate was to launder criminal proceeds, the officials said it is unlikely yakuza are focusing on the U.S. as it is ahead of Japan in fighting organized crime.