Chinese President Xi Jinping on Monday called for Central African Republic authorities to "severely punish" the killers of nine Chinese nationals in an attack on a mine.

Xi "has given important instructions, demanding an all-out effort to treat the wounded, handle the aftermath in a timely manner, severely punish perpetrators in accordance with the law, and ensure the safety of Chinese citizens", an unnamed China foreign ministry spokesperson said in a statement.

Raiders have killed nine Chinese nationals in an attack on a mine in the Bambari region of troubled Central African Republic, a local mayor said Sunday.

"We have counted nine bodies and two wounded," the mayor of Bambari, Abel Matchipata, told AFP, adding that the victims were Chinese workers at a site run by the Gold Coast Group, 25 kilometres (15 miles) from his town.

The attack by "armed men" happened around 5:00 am, he added.

A local security source confirmed the toll and the nationality of the victims.

The Chinese embassy gave no immediate reaction, when contacted by AFP.

The local authorities did not release further details of the attack, nor was there any claim of responsibility.

The victim's bodies were transferred to a hospital in Bangui, where Chinese ambassador Li Qinfeng and CAR Foreign Minister Sylvie Baipo Temon attended, an AFP journalist noted.

Civil conflict has hit the Central African Republic, one of the world's poorest countries, since 2013 when Muslim-dominated armed groups ousted president Francois Bozize.