Nine people have recently been arrested by Beijing police for scalping tickets for the National Museum of China, the capital's Public Security Bureau said on Thursday.

Three were given administrative punishments, while the other six were placed under criminal detention, according to a statement released by the bureau on its Sina Weibo account, a Chinese Twitter-like platform.

The museum, with its major collection of artifacts and art and which serves as a kind of national 'cultural parlor', is open to public for free. Visitors must make real-name online appointments through its official website, WeChat mini program or app, and one mobile phone number may book tickets for up to five people up to a week in advance.

"But we found the some mobile phone numbers were used to book and refund tickets multiple times within a month, which was inconsistent with normal behavior," the bureau said, noting that the scalpers allegedly took advantage of visitors unfamiliar with the appointment procedures to cheat them out of money.

"Some scalpers, for example, were discovered to have helped visitors book tickets online and then accepted service fees ranging from 10 yuan ($1.3) to 30 yuan, and some travel agencies were found to have included the free admission to the museum in their tour guide expenses," it added.

The bureau reminded visitors to use the museum's website, app or WeChat mini program to book online. It also encouraged anyone discovering scalpers to call the police as quickly as possible.