Russia has moved some troops onto an airbase in Niger where a small number of US forces remain, but Defence Secretary Lloyd Austin said he doesn’t see it as a significant issue. According to a US official, most American troops previously stationed at that base in Niamey have departed. The arrival of Russian trainers in the West African country about three weeks ago came in the wake of Niger’s decision to order out all US troops. The order has impacted US military operations in the Sahel, a large region south of the Sahara Desert where groups linked to al-Qaida and the Islamic State group are a…