BEIJING, March 31 (Xinhua) -- Beijing reported three new imported cases of COVID-19 Monday, two of whom coming from Serbia and one from Spain, a local health official said Tuesday.

   It was the first time that Beijing has reported imported COVID-19 cases from Serbia, said Pang Xinghuo, deputy head of the municipal disease control and prevention center at a press conference.

   The two cases from Serbia are a couple. They and their two sons departed Serbia on March 18 and arrived in Beijing on March 19 via Moscow on flight SU204.

   The four of them were put under concentrated quarantine and observation after deplaning. The couple showed symptoms including fever on March 27 and 28, respectively, and were confirmed to have been infected with the novel coronavirus on Monday.

   Their two sons tested negative for coronavirus, though one of them had a sore throat and was under close observation.

   Pang said the couple showed symptoms on days nine and 10 after returning to China, which demonstrated the necessity of carrying out 14-day observations.