At least 17 people have been killed in clashes between Niger's army and Tuareg fighters who have been waging a sporadic insurgency for more than a year, according to statements issued by both sides.

The Niger government said only Tuareg fighters were killed and no government soldiers died in the fighting on Friday.

Both the government and the fighters confirmed battles around the town of Tezirzait, a town in the northern uranium-producing Agadez region.

Among the dead was a senior Tuareg member, the government statement said.

The Tuareg fighters, allies of the Niger Movement for Justice (MNJ), said on its website that 26 soldiers died in two other separate clashes in the area, along with seven of its own fighters.

The government operation to recapture Tezirzait was announced by Niger's defence ministry following the release of four French hostages by the MNJ on Wednesday. The French were abducted on Sunday.

Both the Tuaregs and the MNJ demand greater autonomy for the West African region and a bigger share of its mineral wealth for local people. 

Encouraged by rising world prices for uranium, the radioactive fuel for nuclear reactors, Niger hopes to become the world's 2nd largest uranium producer by 2011.