A packer setting tool sets a liner top packer by mechanical rotation of the running tool and set down weight following cementing of a liner. The packer setting tool includes a tubular release body mounted on an end of the running tool. An annular dog sub circumscribes a portion of the release body. The dog sub is linked to the release body with a shear screw. A thread on an outer surface of the release body engages a thread on an inner surface of the dog sub to define a threaded connection between the dog sub and the release body. When the running tool rotates, the thread on the release body rotates with respect to the thread on the dog sub driving the release body in an axial direction fracturing the shear screw and urges an adapter sleeve against the packer assembly to set the packer assembly.