TOKYO (Kyodo) -- The number of yakuza members and associates in Japan fell to a record low of 18,800 at the end of last year amid a rise in anonymous, ad hoc criminal groups, National Police Agency data showed Thursday.

Membership fell below 20,000 for the first time since records began in 1958, as the number of organized crime members has been steadily declining since 2005 amid strict crackdowns.

The revelation comes as the agency data also showed that 10,105 members of anonymous, ad hoc criminal groups known as "tokuryu" were investigated for profit-motivated crimes in 2024, with authorities struggling to crack down on the masterminds who operate from the shadows. It marks the first full-year enforcement statistics on the groups.

Of the total, 3,925 individuals were recruited through social media with promises of lucrative "yami baito," a term that refers to illicit part-time work.

The agency has been ramping up efforts to crack down on tokuryu groups over their involvement in a series of violent robberies in Tokyo and its surround areas, and fraud schemes, including various investment and romance scams on social media, which resulted in a collective estimated record loss of around 200 billion yen ($1.4 billion) in 2024.

According to the data, 5,203 of the apprehended members were involved in five major crimes. Fraud was the most common, with 2,655 cases, followed by theft at 991, drug-related offenses at 917, robbery at 348 and violations of the adult entertainment law at 292.

While 633 members were classified as masterminds or coordinators, they are believed to be mid-level operatives rather than top leaders, suggesting that the highest ranks of these organizations remain out of reach.

Outside the five major categories, another 4,902 individuals were involved in crimes such as selling bank accounts for illicit transactions and money laundering.

Despite the decline in yakuza membership, police have discovered cases of the groups profiting from tokuryu activities by bringing them under their umbrella.

In some cases, current or former gang members have been identified as leaders or participants in tokuryu-related crimes.