A massive recruitment poster for Russia’s Wagner mercenary force has appeared on the facade of a north-east Moscow office building next to a highway.

The 17-story-high advertisement features the group’s logo and slogans such as “Join the winning team!” and “Together we will win,” as well as a picture of a masked man holding a weapon.

Wagner, which fights alongside Russian forces in eastern Ukraine, has attempted to replenish troop numbers in preparation for a potential Ukrainian counteroffensive.

The group is thought to have sustained heavy losses as it battles for control of the eastern Ukrainian city of Bakhmut, in what has become the longest, bloodiest battle of the war.

Its boss Yevgeny Prigozhin, a 61-year-old ex-convict whose company grew wealthy by catering events and fulfilling contracts for the Kremlin and government ministries, said earlier in March that he aimed to recruit 30,000 new fighters by mid-May.

Private military companies are not allowed to operate inside Russia under the constitution, but can work abroad.

Moscow has backed Wagner with equipment and arms, and has made extensive use of its forces during its military campaign in Ukraine.