Hongik University Station on Line No. 2 had the greatest number of hidden camera crimes reported, followed by Express Bus Terminal Station and Gangnam Station, a local subway operator said Tuesday.

According to Seoul Metro, 83 cases of hidden camera crimes -- secretly installed cameras or photos taken without permission -- were reported from Hongik University Station to the subway squad of the Seoul Metropolitan Police Agency last year. It is the second time the station has topped the list that is compiled from all stations on subway Line Nos. 1 to 8. In 2016, 94 cases were reported at Hongik University Station.

Express Bus Terminal Station, which is a transfer station for Line Nos. 3 and 7 tied for second at 51 cases, followed by Gangnam Station on Line No. 2 and Seoul Station on Line Nos. 1 and 4, which recorded 45 cases each.

Sindorim Station on Line Nos. 1 and 2 had 38 reported hidden camera crimes, while Sadang Station of Line Nos. 2 and 4 had 34 cases, Daerim Station of Line Nos. 2 and 7 had 30 cases. Seoul National University Station and Yeoksam Station, both on Line No. 2, had 17 cases and 14 cases, respectively.

Despite preventive efforts by the subway operator and police, reported hidden camera crimes have gone up, reaching 643 cases inside Seoul subway stations last year, Seoul Metro said. In 2016, 586 cases were reported.

Last year, 294 cases were reported from Line No. 2, accounting for 45.7 percent of all reports. Line No. 1 followed with 85 cases, No. 4 with 75 cases, No. 7 with 72 cases and No. 3 with 64 cases. Only one case was reported on line No. 8.

Seoul Metro said it has 50 female security guards on duty three days a week from 10 a.m. to 5 p.m. to regularly check the 255 subway stations in Seoul.

“Separate from the subway police squad, we also have 295 subway security guards to protect passengers from possible crimes. And we also show a sex crime prevention video 40 times a day on screens inside the stations,” a Seoul Metro official said.

By Jo He-rim (herim@heraldcorp.com)