A deadly gun battle along the China-Vietnam border has left seven people dead, including five Chinese migrants and two Vietnamese border guards.

According to local officials, a shootout erupted when Vietnamese border guards tried to turn back a group of Chinese citizens entering their country illegally.

In a statement, the Quang Ninh provincial government in Vietnam said a total of 16 Chinese nationals, including 10 men, four women and two children were detained after attempting to enter Vietnam.

While Vietnamese authorities were attempting to repatriate them, "some Chinese men in this group seized guns from Vietnamese border guards and shot at them", the statement said.

The statement also said the firefight erupted despite efforts to calm the situation.

Details of the bloody clash remain scarce and it is unclear if the dead included Chinese women and children.

Vietnamese media has reported that the Chinese citizens were from the far Western Muslim Province of Xinjiang where human rights groups say there is persecution of local ethnic Uighurs.

The area has reported human trafficking and people smuggling cases, including the kidnapping of Vietnamese women forced to marry Chinese men and young boys being kidnapped for sale to rich childless Chinese couples.

Irregular migration from the Chinese side is unusual, with more Vietnamese migrants wanting to travel north to find work in large Chinese cities.