Have moving character aim at a target

I want to have a character run towards one target, and have it’s upper body and weapon track to another target that is not in front of it. This will be for a character that is running somewhere while shooting somewhere else.

I have a running animation for the legs, and I have a shooting animation for the arms. But I somehow need to have it track towards a certain target.

Can anyone give me a clue for where to start with this?