Troops from the rebellious Wagner mercenary group are out in force in the city of Rostov-on-Don outside the army headquarters for Russia's southern military district, with passers-by stopping to look at the military vehicles. Wagner chief Yevgeny Prigozhin says his troops have taken control of the headquarters, Russia's main command centre for Ukraine operations, as well as an airbase in the city, vowing to topple Moscow's top military leaders. IMAGES