CHINA'S most popular mobile messaging service WeChat experienced an outage this morning, the first major breakdown in its two-and-a-half-year history.

Many users reported they failed to send or receive messages through WeChat and were unable to have access to public accounts starting around 8am this morning.

"I wonder if my phone is broken and I sent my friends text messages only to find out their WeChat is down as well," WeChat user Emma wrote on her microblog.

WeChat, operated by China's largest Internet company Tencent, has more than 300 million users and nearly 70 million overseas users.

"A communications optical fiber cable was damaged in municipal construction projects and we're putting back our services as soon as we can," Tencent said in an official microblog posting at noon. "Engineers are working to fix the broken fibers and we're sorry for any inconvenience." Tencent later confirmed that the damaged cable is in Shanghai.

WeChat has become a major communication channel between smart phone users and it has gradually evolved into a platform for articles and postings to be shared between friends.

"WeChat itself has already become a basic network for many users," said one microblog users with the ID "Justokay".