Beijing has unveiled new measures to curb the spread of COVID-19 as the city reported two new cases in a day.

Authorities in Beijing have urged residents not to leave the city unless necessary and restricted those in regions with new infections from entering the Chinese capital, Xu Hejian, a spokesperson for the Beijing municipal government, told a press briefing on Monday.

Since last week, more than a dozen cases have been reported in the Chinese capital. Local authorities said the cases are linked to tourist groups visiting north China's Inner Mongolia Autonomous Region.

A pair is under criminal investigation for violating epidemic control measures. Despite having developed a sore throat and fever, they invited others to play mahjong and went out for meals upon their return from Inner Mongolia Autonomous Region. Five others who joined the mahjong table have been confirmed with the virus by Monday.

All those traveling into Beijing should present a "green code" that proves they have not been in coronavirus risk areas, Xu said.

Authorities have suspended trans-provincial group tours. Local parks, theaters and museums are currently permitted to operate at 75 percent capacity. 

People are encouraged to use video conferences to replace in-person meetings. The Beijing marathon, which was scheduled to take place on October 31, was postponed.

Beijing reported two locally transmitted confirmed COVID-19 cases and one asymptomatic case between 4 p.m. Sunday and 3 p.m. Monday, said Pang Xinghuo, deputy director of Beijing's center for disease control and prevention. The two confirmed cases, a couple, had traveled with another two cases reported on Sunday, Pang said.

(With input from Xinhua)