BEIJING (Reuters) - China's three biggest airlines have restored a fraction of the international flights they halted in the wake of a coronavirus outbreak, heeding a call from the aviation regulator as business activity recovers slowly.

Air China resumed flying on Friday to the German commercial hub of Frankfurt from the southwestern city of Chengdu, following a 21-day suspension over the epidemic, state-run Xinhua news agency said.

China Southern Airlines had recommenced flights on Tuesday to the Kenyan capital of Nairobi from the southern city of Guangzhou as demand revived on recovering trade with the African country.

Data from industry intelligence firm CAPA showed the numbers of airline services from China to Cambodia, France, Germany, the Philippines and Thailand, were up this week from the last.

China's aviation industry is one of the worst-affected by the epidemic, following travel curbs by nations fearing contagion and cancellations by airlines on shrivelling demand.

Almost 2,800 people have died in the outbreak in mainland China, where the tally of infections stands at 78,800.

(Reporting by Stella Qiu in Beijing and Brenda Goh in Shanghai; Editing by Clarence Fernandez)