The United Nations human rights chief is "gravely concerned" about a rise in killings of civilians across Burkina Faso, his office said Friday, demanding an independent investigation and accountability.

Between November 2023 and April 2024, Volker Turk's office said it had received allegations of violations and abuses of international human rights and humanitarian law affecting at least 2,732 individuals -- a 71-percent increase from the previous six months.

Some 1,794 of those were victims of unlawful killing.

"While armed groups are presumed responsible for the vast majority of incidents and victims and should be held accountable, I am also deeply disturbed that security and defence forces and their auxiliaries... allegedly carried out wanton killings, including summary executions," Turk said in the statement.

The army has governed Burkina Faso since 2022, carrying out two coups that it said were justified in large part by the persistent insecurity.

Jihadist rebels affiliated with Al-Qaeda and the Islamic State group have waged a grinding insurgency since 2015 that has killed thousands and displaced millions in the West African country.

Turk said he appreciated Burkina Faso was facing complex security threats, but any response to those threats would only work if international law was fully respected.

"I therefore reiterate my call to the authorities in Burkina Faso to take all possible measures to ensure the protection of civilians," the UN high commissioner for human rights said.

He called on the government to support a thorough, independent, and transparent investigation into all allegations of violations and abuses of international law, and to ensure that perpetrators are brought to justice, in trials that meet international standards.

"There must be justice and accountability if the authorities are to reassure the population, restore social cohesion and rebuild trust between civilians and the security forces," Turk said.

Landlocked and lying in the heart of the Sahel region, Burkina Faso is one of the world's most volatile and impoverished nations. It has experienced repeated coups since gaining independence from France in 1960.

Human rights groups have accused Burkina's junta leaders of abuses against civilians during their military campaigns against jihadists, and of silencing media and opposition leaders.