A few Chinese border cities are halting some non-container commodity imports by rail to reduce the risk of COVID-19 clusters caused by the virus brought in from other countries amid a resurgence of infections in northern areas of China. China's efforts to keep the virus out face increasing pressure as infections grow globally with the new threat of the Omicron variant, Mi Feng, a spokesperson for the National Health Commission, said on Tuesday. The city of Manzhouli in the northern Chinese region of Inner Mongolia, a small border town near Russia, said from Wednesday it would suspend taking some non-containerised rail cargo arriving from abroad that requires manual loading and unloading, including coal and fertiliser. The measure comes as Inner Mongolia reported a total of 41 domestically transmitted cases with confirmed symptoms on Sunday and Monday. More than half of the cases were found in Manzhouli. The outbreak is much smaller than many outside China, but Beijing has taken a zero-tolerance approach to clusters, with cities quickly imposing travel restrictions and closing public venues. read more Gene sequencing results on samples from a few Manzhouli infections indicated that the latest flare-up was caused by a virus source from overseas unrelated to previous outbreaks elsewhere in China, an official said on Tuesday. Erenhot, a key transit hub in Inner Mongolia next to Mongolia itself, halted some non-containerised imports by rail that need to be handled by hand, according to a local government statement. These included certain cargos for coal, oil, copper ore, zinc and iron ore. Erenhot did not report any new local infections over the weekend. Suifenhe, in northeastern Heilongjiang province on the border with Russia, on Tuesday halted some non-containerised imports, such as coal and fertiliser. read more Heilongjiang detected one domestically transmitted asymptomatic carrier on Sunday in a different city. The three cities did not say when the restrictions might be lifted. Authorities in China, where the virus was first identified in late 2019, vowed this month to step up virus control in border areas, demanding strict implementation of prevention measures on imported cargo. read more The northeastern cities of Huichun and Dongning, both along the border with Russia, in mid-November suspended some non-essential imports by highway, such as wine, milk and chocolate. Reporting by Roxanne Liu and Gabriel Crossley; Additional reporting by Beijing Newsroom; Editing by Christopher Cushing, Edwina Gibbs and Nick Macfie Our Standards: The Thomson Reuters Trust Principles.