The popular Japanese video-sharing website Niconico has suspended its services due to a cyberattack, its operator announced.

"Currently, Niconico is under a large-scale cyberattack, and we are suspending our services to minimize its impact," operator Dwango said in a statement late Saturday.

"We are now conducting a thorough investigation and implementing countermeasures. However, we will not be able to restore the service until we are confident in its safety and have mitigated the impact of the cyberattack," it said, adding it didn't expect to be able to restore the service this weekend.

Niconico is one of Japan's largest video-sharing services, where users share a wide variety of videos, from music and sports to various hobbies. It also offers live streaming of programs, including government officials' press conferences.

In addition to Niconico, its parent company Kadokawa's official website and its e-commerce site, ebten, were also affected by possible "unauthorized access from outside," the publisher said Sunday.

"We sincerely apologize for causing concern and inconvenience due to the issue affecting several websites of the Kadokawa Group since early Saturday morning," the Tokyo-based publisher said.

Kadokawa is investigating the impact from the attack, including "whether there have been leaks of information," and was also cooperating with external experts and police, it said.

Dwango said it would give an update on Monday.