Observers in Kyiv described it as one of the heaviest air attacks in two and a half years of war.
Mr Türk, in a statement, urged the generals to restore constitutional order immediately.
Malian authorities described it as an anti-terrorist military operation against an al-Qaeda-affiliated group known as Katiba Macina.
At least 209 people have been executed since January 1 this year, according to sources quoted by the UN rights office (OHCH).
UN senior officials on Wednesday called for an investigation into the killing of a well-known Al Jazeera correspondent, Ms Shireen Abu Akleh.
