Members of Chinese medical expert team to Serbia learn about the epidemic prevention and treatment measures of local hospitals in Novi Pazar, Serbia, April 10, 2020. A team of Chinese medical staff with experience in fighting COVID-19 arrived in Serbia on March 21, 2020 to help with the Balkan state's battle against the virus. Over the past three weeks, they have shared their experiences in fighting the COVID-19, as well as offered advise on measures that have produced the best results in China in preventing the spread of COVID-19. (Chinese medical expert team to Serbia/Handout via Xinhua)

A member (L) of Chinese medical expert team to Serbia visits a clinic in Belgrade, Serbia, April 11, 2020. A team of Chinese medical staff with experience in fighting COVID-19 arrived in Serbia on March 21, 2020 to help with the Balkan state's battle against the virus. Over the past three weeks, they have shared their experiences in fighting the COVID-19, as well as offered advise on measures that have produced the best results in China in preventing the spread of COVID-19. (Chinese medical expert team to Serbia/Handout via Xinhua)

Members of Chinese medical expert team to Serbia visit a clinic in Belgrade, Serbia, April 11, 2020. A team of Chinese medical staff with experience in fighting COVID-19 arrived in Serbia on March 21, 2020 to help with the Balkan state's battle against the virus. Over the past three weeks, they have shared their experiences in fighting the COVID-19, as well as offered advise on measures that have produced the best results in China in preventing the spread of COVID-19. (Chinese medical expert team to Serbia/Handout via Xinhua)

A local citizen greets Peng Zhiqiang, chief of the Chinese medical expert team to Serbia, in Belgrade, Serbia, April 11, 2020. A team of Chinese medical staff with experience in fighting COVID-19 arrived in Serbia on March 21, 2020 to help with the Balkan state's battle against the virus. Over the past three weeks, they have shared their experiences in fighting the COVID-19, as well as offered advise on measures that have produced the best results in China in preventing the spread of COVID-19. (Chinese medical expert team to Serbia/Handout via Xinhua)

Members of Chinese medical expert team to Serbia pose for a group photo at their residence in Belgrade, Serbia, April 12, 2020. A team of Chinese medical staff with experience in fighting COVID-19 arrived in Serbia on March 21, 2020 to help with the Balkan state's battle against the virus. Over the past three weeks, they have shared their experiences in fighting the COVID-19, as well as offered advise on measures that have produced the best results in China in preventing the spread of COVID-19. (Chinese medical expert team to Serbia/Handout via Xinhua)

Members of Chinese medical expert team to Serbia learn about the epidemic prevention and treatment measures of local hospitals in Novi Pazar, Serbia, April 10, 2020. A team of Chinese medical staff with experience in fighting COVID-19 arrived in Serbia on March 21, 2020 to help with the Balkan state's battle against the virus. Over the past three weeks, they have shared their experiences in fighting the COVID-19, as well as offered advise on measures that have produced the best results in China in preventing the spread of COVID-19. (Chinese medical expert team to Serbia/Handout via Xinhua)