The Czech cyber watchdog issued a warning about using TikTok on Wednesday, joining other Western authorities in deeming the Chinese-owned video-sharing app a security threat.

TikTok has come under growing scrutiny in many countries over concerns the app may give Chinese authorities access to sensitive user data.

The Czech National Cyber and Information Security Agency (NUKIB) warned that TikTok could pose a threat if installed on "devices accessing critical information and communication infrastructure".

"The Agency is concerned about a potential security threat stemming from the use of TikTok primarily due to the amount of user data that is collected by the app as well as the way the data is handled," it said.

The NUKIB added that it was concerned because TikTok's parent company, ByteDance, "falls under the legal jurisdiction of the People's Republic of China".

US lawmakers have introduced a bill to ban the app, which US government workers are already prohibited from installing on their devices.

Civil servants at the European Union, as well as in Canada and Denmark are also barred from having TikTok on their phones.

The Czech government, while part of the EU, has not introduced a ban so far.

In a report published last year, the Czech national intelligence agency BIS singled China out as a major threat targeting Czech cyberspace.

"Chinese technologies penetrating important networks of state infrastructures... can be evaluated as a major security threat," it said.