The 17 men and four women are wanted by the Chinese police for allegedly appropriating property by fraud, Lao Cai newspaper reported.

Around 100 soldiers and police officers raided an apartment block at the Kim Thanh commercial area and found them along with 300 electronic devices, including laptops, tablets and mobile phones.

An investigation showed that they had illegally crossed the border from China and were given refuge by one of them, who has dual Vietnamese-Chinese citizenship.

To avoid suspicion, they had raised chickens and ducks and had a 24-hour lookout while their apartments were guarded by gates and fences.

A series of arrests against illegal Chinese entrants have been made in Vietnam in recent weeks as the country beefed up border control following the resurgence of Covid-19 in late July.