The UN has expressed alarm at the growing recruitment of foreign private military and security companies by the Central African Republic (CAR) government.

It has also raised concern over the close contacts that these companies and their staff maintain with UN peacekeepers in the country.

The country is plagued by armed clashes between the rebel coalition led by ex-president François Bozizé and the national army supported by the UN mission there (Minusca) and Russian military companies.

In a report released on Wednesday, a UN group of experts says they have received reports of serious violations of human rights and international humanitarian law attributable to the military private companies operating jointly with the Central African Armed Forces (FACA) and, in some cases, with the UN peacekeeping forces.

These violations include reports of mass summary executions, arbitrary detentions, torture during interrogation and enforced disappearances.

It also cites the forced displacement of the civilian populations and indiscriminate targeting of civilian facilities and humanitarian actors.

The working group deplores the lack of investigations as well as the lack of determination to identify those responsible for these abuses.

The experts called on the CAR government and its "international partners" to abide by their obligations under international law, and in particular to hold all perpetrators of serious human rights violations and abuses to account.