Authorities in northern China are reimposing lockdowns and other emergency measures to curb the spread of coronavirus, with health officials warning of a worsening outbreak after the country recorded more than 100 cases across 11 provinces over the last week, CNN reported. "Since October 17, there have been multiple scattered local outbreaks in China, and they"re expanding rapidly," Mi Feng, a spokesman at the National Health Commission (NHC), said at a news conference Sunday. "There is an increasing risk that the outbreak will spread even further." The rapid spread comes despite about 75% of China"s population -- or more than a billion people -- being fully vaccinated, according to Mi. The caseload of China"s latest outbreak pales in comparison with those of some other countries, including Singapore and the United Kingdom. But the scope of its spread has worried the Chinese government, which insists on a strict zero-Covid policy to stamp out infections. The outbreak was first detected on October 16 among a tour group of fully vaccinated senior citizens from Shanghai who traveled in several northern regions. Among the 133 infections reported as of Sunday, 106 were linked to 13 tour groups, according to Mi, the NHC health official. Infections have been reported in nearly a third of the country"s provinces and regions, with all medium- and high-risk regions concentrated in Inner Mongolia, Gansu, Ningxia, Guizhou and Beijing. Authorities have banned travel agencies from organizing cross-provincial tours in these regions. On Sunday, the Chinese capital tightened entry restrictions into the city, requiring travelers from places with confirmed cases to present a negative coronavirus test and undergo 14 days of health monitoring. The city has recorded 14 confirmed cases in the latest outbreak, including 12 over the past three days, according to a CNN tally of the Beijing Municipal Health Commission"s daily reports. A widespread Covid outbreak in Beijing would be the last thing Chinese leaders want to see as the city gears up for the 2022 Winter Olympics in February. Next month, members of the ruling Communist Party"s elite Central Committee are also due to gather in the capital for their annual meeting, which paves the way for President Xi Jinping to stay for a third term in power at the party congress next fall. Already, authorities in Beijing are making an example of six residents who allegedly broke Covid rules with criminal detentions. Among them, two went out to eat and invited friends home for mahjong despite having developed fevers upon returning from a Covid-infected tourist destination in Inner Mongolia. Another two tried to climb over the fences of their locked-down gated community. The city also suspended a marathon originally scheduled for October 31. It has not announced a new date for the event. Elsewhere, the Covid response has been even more sweeping and stringent. Ejin Banner, a city of 35,000 people in Inner Mongolia and a popular tourist destination, banned all residents and tourists from leaving their homes or hotel rooms starting Monday, after it recorded 12 cases on Sunday. The city also announced harsh punishment for six officials, including the director of the local health commission, for their "slack response and ineffective management" of the latest outbreak, the state-run Global Times reported Sunday. In neighboring Gansu province, the provincial capital of Lanzhou also announced measures over the weekend to "cease all tourist activities" and put visitors in quarantine. Both cities, as well as several others in Inner Mongolia and Gansu, have suspended all trains, buses and taxi services, according to the Transportation Ministry.