WASHINGTON, July 24 (Reuters) - The United States on Monday (Jul 24) imposed sanctions on three Malian officials, including the minister of defence, over accusations they facilitated the deployment and expansion of the Russian Wagner Group's activities in the West African country.

The US Treasury Department said it imposed sanctions on Mali's Minister of Defense, Sadio Camara, who it said made several trips to Russia in 2021 to solidify an agreement between the Wagner Group and the Malian transition government to deploy the mercenary force.

Monday's sanctions also target Mali’s Chief of Staff of the Air Force Alou Boi Diarra and Malian Air Force Deputy Chief of Staff Adama Bagayoko, the department said.

"These officials have made their people vulnerable to the Wagner Group’s destabilizing activities and human rights abuses while paving the way for the exploitation of their country’s sovereign resources to the benefit of the Wagner Group’s operations in Ukraine," Treasury Under Secretary for Terrorism and Financial Intelligence Brian Nelson said.

Mali's transition government did not immediately respond to a request for comment on the sanctions, which freeze any US assets of those designated and generally bar Americans from dealing with them.

Both Russia and Mali have said Russian fighters in the African nation are not mercenaries but trainers helping local troops fight a decade-long insurgency by Islamist militants.

The Treasury accused Diarra of working with Camara to form and execute the plan that ultimately brought the Wagner Group into Mali and of collaborating with the Wagner Group's head in the country, who is also under U.S. sanctions.

Bagayoko has served as an advocate of the Wagner Group to Burkina Faso's transition government in an effort to secure the force's deployment to the country, the Treasury said, adding that he has also reportedly sought to facilitate the Wagner's Group's access to gold mining in Mali.

Burkina Faso's interim leader Ibrahim Traore in May denied Wagner forces were in the country. His comments followed allegations by Ghana's President Nana Akufo-Addo in December that Burkina Faso had hired the mercenaries.

Wagner has battled in Libya, Syria, the Central African Republic, Mali and other countries, and has fought the bloodiest clashes of the 16-month-old war in Ukraine. It was founded in 2014 after Russia annexed Ukraine's Crimea peninsula and started supporting pro-Russia separatists in Ukraine's eastern Donbas region.

Mali's leaders seized power in a 2021 coup and brought in Wagner after asking a French military mission to leave.

The United States has previously imposed sanctions on Wagner and has repeatedly warned of what it says are Wagner's destabilizing activities as Washington has ramped up sanctions against the private army following Russia's invasion of Ukraine last year.

In June, the United States accused the leader of the mercenary force of helping to engineer the departure of UN peacekeepers from Mali.

Washington also said in May that the Wagner Group may be working through Mali and other countries to hide its efforts to acquire military equipment for use in Ukraine.