The United Nations Multidimensional Integrated Stabilization Mission in Mali (MINUSMA) said on Friday that it was investigating reports of serious human rights violations, including alleged executions of civilians, following armed clashes in north Mali.

"MINUSMA reported that an investigation team has been deployed on Friday in the town of Tin-Hamma, Gao region, to establish the facts following reports of serious human rights violations including alleged executions of civilians following clashes between armed groups," deputy UN spokesman Farhan Haq said at a daily news briefing here.

"MINUSMA is also concerned with the increased number of armed confrontations in northern Mali," Haq said. "The Mission condemns the continuous violations of ceasefire that jeopardize the peace process."

MINUSMA deplores that the humanitarian access is also affected as a result of the violence and calls on all parties to respect their obligations under international humanitarian law, he said.

UN-brokered peace efforts in Mali's north risk unraveling due to repeated violations of a ceasefire between the Tuareg-led Coordination of Movements of Azawad (CMA) and the pro-government factions around the flashpoint northern town of Menaka.

The clashes on Thursday killed at least six civilians, including a Malian aid worker, rebels and a local source said.

Since a military coup struck Mali in March 2012, its northern region has served as a stronghold of the rebels.

Mali is now in the process of restoring democracy with the help of the United Nations and African regional bodies, including the African Union and the Economic Community of West African States ( ECOWAS).

Despite initial security improvements in 2013, the situation in northern Mali has deteriorated since the beginning of 2014. An increase in incidents involving improvised explosive devices, mostly targeting Malian and international security forces, has impeded the return to normalcy and resumption of economic and development activities.