Telecommunications in the quake-hit northwest China region have been restored, the Qinghai provincial government said Thursday.

Both fixed-line and mobile phone links in the region had been available since early Thursday, said Liu Yougui, director of the government information office, at a press conference.

The 7.1-magnitude quake, which struck the Tibetan Autonomous Prefecture of Yushu in southern Qinghai early Wednesday, has left 617 dead, 9,110 injured and 313 missing.

The deadly quake also toppled 15,000 residential buildings and forced 100,000 residents to be relocated, according to the rescue headquarters.

Thousands of rescuers have been fighting altitude sickness, chilly weather, strong winds and frequent aftershocks to dig through rubble to reach survivors.

The earthquake has damaged roads, disrupted telecommunications and knocked out power.

Roads to the quake-hit Yushu County from Xining City, the provincial capital, were passable for the increasing numbers of rescuers and relief materials rushing to the region from all over the country, said Liu.

Roads linking the airport and Gyegu, the hardest-hit, had been repaired after being blocked by quake-triggered landslide.

The provincial government had mobilized 294 passenger buses from transport companies and travel agencies to support the quake relief operations, he added.

Meanwhile, 484 trucks with a total capacity of 5,955 tonnes were on call 24 hours a day.