At least eight Malian soldiers have been killed in an ambush on a military convoy in the country's west-central region, according to an army spokesman.

Armed assailants attacked the troops' vehicle on Tuesday after it hit a mine near the town of Nampala in the restive Segou province.

"The provisional toll is eight dead and some people wounded," Colonel Diaran Kone, an army spokesman, told the Reuters news agency, holding unspecified groups responsible.

There was no immediate claim of responsibility, but rebel groups - some linked to Al-Qaeda in the Islamic Maghreb (AQIM) - have stepped up a series of attacks in recent months in a campaign against the Malian government and its international allies.

READ MORE: Tuareg factions to boycott Mali peace conference

Last July, 17 soldiers were killed in an attack on a military base in Nampala, which sits close to the Mauritanian border. The attack was claimed by the Ansar Dine group.

A similar attack on the garrison town in January 2015 claimed the lives of 11 Malian soldiers.

Northern Mali fell to groups linked to AQIM in March 2012. They were driven out of key towns by a French-led military intervention the following year, but have now spread further south.

The Mali security forces are struggling to keep security despite the presence of French and United Nations troops.

Last weekend, the government extended a state of emergency by six months.

Three Malian groups with previous al-Qaeda links recently joined forces to create the "Group to Support Islam and Muslims" (GSIM), led by Iyad Ag Ghaly of Ansar Dine, and have already killed soldiers further east near the Burkina Faso border.

France said it killed more than 20 fighters hiding in a forest near the border last weekend in an operation that involved both air and ground strikes.