UK sanctions have been announced against "despicable" individuals linked to massacre, rape and torture carried out by the Wagner Group across Africa.
Foreign Office minister Andrew Mitchell said the Russian mercenary unit, as well as assisting the Kremlin with its invasion of Ukraine, was "acting with impunity" in countries such as Mali, Central African Republic (CAR) and Sudan.
Mr Mitchell on Thursday announced 13 sanctions in a package aimed at individuals and businesses.
Officials said Wagner has operated in Mali, CAR and Sudan for several years where it is "aggressively pursuing Russian foreign policy interests" and providing military support to counter-terrorism operations which have seen hundreds of civilians killed.
Three of the sanction designations were targeted at the group's top officials in Mali and CAR, including Konstantin Aleksandrovitch Pikalov, the so-called right-hand man of Wagner leader and oligarch Yevgeny Prigozhin.
The UK Government said Mr Pikalov had been responsible for the torture and targeted killing of civilians.
Another of those hit with sanctions was the head of the Wagner Group in Mali, Ivan Aleksandrovitch Maslov.
According to the Foreign, Commonwealth and Development Office (FCDO), Wagner mercenaries, alongside Malian forces, massacred at least 500 people in Moura in March 2022, including carrying out summary executions, rape and torture.
Wagner leader Mr Prigozhin, who led a mutiny against Moscow last month, has already been sanctioned by Britain, along with several of his key commanders, for their part in Russian president Vladimir Putin's attack on Kyiv.
Footage has recently emerged which appears to show the Wagner mercenary leader, greeting his fighters in Belarus, in what would be his first public appearance since he led last month's uprising.
Mr Mitchell, the Conservative minister for development and Africa, said: "The Wagner Group is committing atrocities in Ukraine, as well as acting with impunity in countries like Mali, Central African Republic and Sudan.
"Wherever Wagner operates, it has a catastrophic effect on communities, worsens existing conflicts and damages the reputations of countries that host them.
"These sanctions expose despicable individuals who have commissioned violations of international humanitarian law, holding them to account for the severe harm they are inflicting on innocent civilians for financial gain."
The Wagner sanctions come a week after the UK imposed punishments and restrictions on businesses linked to the leaders on both sides in the Sudanese conflict.
The measures applied to three businesses associated with the Sudanese Armed Forces and three linked to its rival in the power struggle, the Rapid Support Forces.
Britain has accused the Wagner Group of providing weapons and military equipment to fighters in Sudan.
It said three businesses acting as fronts for Mr Prigozhin's unit had been included in Thursday's sanctions package, citing the continued risk the firms – including M-Invest and its subsidiary Meroe Gold – pose to peace and stability in the country.
Senior Labour figures, including shadow foreign secretary David Lammy and shadow home secretary Yvette Cooper, have called on the Government to proscribe Wagner as a terror organisation for its role in the Ukraine conflict.
Wagner forces played a major part, albeit with reports of heavy casualties during fierce fighting, in capturing the salt mining city of Bakhmut in the Donetsk region for Moscow earlier this year.
Ministers have so far refused to proscribe the organisation, pointing instead to the extensive sanctions applied by Britain on the group's leadership.