Six Chinese have been arrested on suspicion of fabricating or trading bogus alien registration cards and other identification documents in three separate cases in Aichi, Saitama and Chiba prefectures, police said Tuesday.

The National Police Agency suspects a large-scale syndicate is behind the three cases, because a similar technique was apparently used to forge more than 5,000 bogus cards.

The forgeries have all been embedded with sophisticated holograms, with some of the suspects saying they brought them from China, the NPA said.

The NPA said they are suspected of fabricating alien registration cards using personal computers and printers at condominiums in Tokyo. The cards sold for about 15,000 yen to 20,000 yen apiece, one of the suspects was quoted as saying.

Aichi police arrested two on suspicion of using fake alien registration cards. The arrests followed their search of a condominium in Meguro Ward, Tokyo, in April. In the search, police seized a PC containing data for more than 3,000 cards, including driver's licenses, student identification cards and alien registration cards.

Police suspect the two have sold bogus cards to foreigners from about 40 countries via more than 30 brokers in 17 prefectures.

Saitama police arrested two people on suspicion of forging and selling fake alien registration cards and passports, and three for buying them.

In Chiba, prefectural police arrested a Chinese woman and her younger sister on suspicion of making fake alien registration cards.