THE first major disruption at WeChat, a popular mobile chatting service in China, left its operator Tencent scrambling to restore order yesterday.

Tencent, China's largest Internet company, promised to strengthen its emergency tolerance system in order to avoid a repeat of the outage.

Starting around 8am yesterday, many users complained that they could not send or receive any messages through WeChat and had problems reading posts sent by verified accounts. It was the first major outage for WeChat in its 2-1/2-year history. The service was restored at around 3pm.

"A communication optic cable was damaged at a municipal construction site in Shanghai and about 30 percent of total messages being transmitted during the five-hour breakdown were affected," a Tencent official told Shanghai Daily. "We will improve our backup structure and boost our emergency tolerance system."

WeChat has accumulated more than 300 million users and boasts nearly 70 million overseas users.

"Large Internet companies should strengthen their telecommunication capacity as popular Internet tools such as Tencent's WeChat now have a huge responsibility towards their users," said Zeng Tao, a telecommunications researcher at Horizon Research Consultancy Group.

The chatting app has become a major communication tool among smartphone users and it has gradually evolved into a platform for articles and postings to be shared between friends.