China's instant messaging app WeChat is seen on a phone in Moscow, Russia, May 6, 2017. (Xinhua/Shi Hao)

MOSCOW, May 11 (Xinhua) -- Russian telecommunication watchdog Roskomnadzor said Thursday that it has allowed access to Chinese instant messaging app WeChat after the service was first blocked last week.

Roskomnadzor said it has received the necessary information needed to properly register the app.

Last week, Roskomnadzor blocked WeChat, saying its operator failed to provide the contact information necessary for registration with authorities.

As a result, some WeChat users in Russia were unable to log in or send messages, while others were not affected.

WeChat is the most popular messenger app in China and is widely used by Chinese living overseas. It is developed by IT giant Tencent Holdings.