Power steering fault?

I have a 94 k11 1.3 auto, and when its cold, weather and the engine's cold it makes a squealing noise like a belt is slipping when i turn the steering wheel. once its warmed up slightly it is fine its just the first minute or so. it also gets harder to steer when its squealing which makes me think its either the belt for the power steering pump or the pump itself
any ideas?