An enormous fire has engulfed a skyscraper in the Chinese city of Changsha, state media reported. Footage posted on social media showed massive flames racing up the 42-story building"s side as office workers rushed to evacuate the building. Thick clouds of black smoke billowed out of the structure, which is a regional office for China Telecom. Authorities said the flames have since been extinguished and that no casualties had yet been reported. Images posted on social media showed firefighters aiming jets of water at the blackened facade of the 218m (715ft) tall structure in a race to put the fire out. An entire side of the skyscraper appeared to be engulfed in flames at one point. In another video, dozens of people could be seen fleeing the scene as flaming debris rained down from the skyscraper"s upper floors. The BBC has not yet been able to verify the footage and it is not currently clear what caused the fire. According to state media, the building was completed in the year 2000 and is positioned near a major ring road in the city of Changsha, the 10-million person capital of Hunan province, in south-central China. In a statement reported by AFP news agency, state-owned telecommunications company China Telecom confirmed the incident, saying it was extinguished "by around 16:30 (local time)". "No casualties have yet been discovered and communications have not been cut off," a company spokesperson said. Sizeable fires are a common occurrence in China, where earlier this year a huge chemical plant in Shanghai erupted in flames. — BBC