BERLIN, Jan 19 (Reuters) - Mali"s authorities banned a German military plane with 75 troops on board from overflying the country late on Wednesday, forcing it to divert to Gran Canaria, the German defence ministry said. The transport plane was on its way from a German air base to a logistics hub in Niamey in Niger when it was told it could not enter Mali"s airspace, a spokesman for the defence ministry in Berlin said. Germany has deployed some 1,200 troops to Mali and has to decide by the end of May whether to extend the military mission which is supplied via the logistics base in Niamey. Berlin has voiced concern over the latest developments in Mali after the arrival of private military contractors of the Russian Wagner Group and the interim authorities" failure to hold democratic elections next month as agreed following a 2020 military coup. "When we are told that the elections are being postponed for five years, things are clearly not moving in the right direction," German Defence Minister Christine Lambrecht said last week, adding she expected democratic progress and a solution to the Wagner group issue if German troops were to stay in Mali. The European Union has announced that it will impose sanctions on Mali in line with measures already taken by the ECOWAS grouping of West African states. Decisions are likely by the end of January. read more