The death toll from a coronavirus outbreak in mainland China rose to 1,523 as of the end of Friday, after 143 people died over the course of the day, the country's National Health Commission said on Saturday morning.The number of new deaths in central Hubei province, at the epicenter of the coronavirus outbreak, rose by 139 as of Friday. Most of the new deaths were in Hubei's provincial capital of Wuhan, where the virus is believed to have originated, with 107 new deaths. A total of 1,123 people in Wuhan have now died from the coronavirus.There were 2,641 new confirmed infections across mainland China, bringing the national total to 66,492. A number of trade fairs and industry conferences in China and overseas have been postponed due to transportation curbs and concerns about the spread of the virus. International Business Machines Corp said on Friday it had canceled its participation in the RSA cyber security conference in San Francisco due to coronavirus-related concerns."The health of IBMers is our primary concern as we continue to monitor upcoming events and travel relative to Novel Coronavirus (COVID-19)," the company said in a tweet.The event is scheduled to take place Feb. 24–28.Earlier in the day, Facebook Inc said it had canceled its global marketing summit scheduled for next month, also in San Francisco, over concerns about coronavirus-related risks. The Mobile World Congress (MWC), the annual telecoms industry gathering in Barcelona, was also canceled after a mass exodus by exhibitors linked to the coronavirus.