All the COVID-19 cases reported in Beijing during this week are related to trips in Inner Mongolia autonomous region directly or indirectly, senior specialist said in the capital on Sunday.

The virus is on the same transmission chain as recent cases in Inner Mongolia and Gansu after experts' investigation of the virus genome, said Pang Xinghuo, deputy director of the Beijing Center for Disease Control and Prevention, at a news conference.

Beijing reported five new locally transmitted cases between Saturday noontime and 3 pm Sunday. Three of the new patients were close contacts of the previous cases in Changping district who had traveled to northwestern China, including Gansu province, and had invited friends to play card after coming back.

The other two new patients have been to Inner Mongolia, Gansu, Shaanxi and Shanxi between Oct 10 to 21 by car.

As the number of confirmed cases increases, the capital has strengthened the control and prevention measures.

Pan Xuhong, spokesperson of Beijing police, said people from the counties where one or more local cases had been reported in the past 14 days should not come to Beijing unless absolutely necessary. Those who need to come to Beijing must bring a green health code and negative nucleic acid testing result within 48 hours. And they should follow a 14-day health monitoring after arrival in the city.

The city has also strengthened the supervision of all drugstores, asking them not to sell febrifuge or cough medicines to patients with fever and to send the patients to designated clinics.