China will increase the frequency of COVID-19 testing by targeting incoming travelers from high-risk regions and stepping up management of port workers and imported cargoes, as part of measures to strengthen virus containment amid the emergence of a new coronavirus variant, health officials said on Tuesday.

Cui Gang, an official from the National Health Commission's disease prevention and control bureau, said that recent domestic outbreaks were all triggered by imported cases spreading via port cities into China.

He said defense against imported infections should be further strengthened, especially at port cities, including closely following the pandemic situation overseas and stepping up local monitoring and precaution systems.

"For people and goods coming from foreign countries and regions, it is required to roll out more frequent tests, limit incoming passenger traffic and implement the circuit-breaker policy for international flights," he said.

Cui added that authorities should expand screening in key areas and groups based on local circumstances.

In addition, port workers and other personnel who tend to come into direct contact with incoming travelers or imported goods should be managed in a closed-loop.

Port cities seeing a large number of cold-chain imports should establish a warehouse designated for sanitizing and testing imported products, he added.

Mi Feng, spokesman of the commission, said the number of daily new infections worldwide is nearing a recent high. "The spread of the Omicron strain has further piled pressure on China's efforts to stave off imported infections," he said.