Minor clashes had been occurring since 1987 .
When the scale of unrest grew , Hu responded with the deployment of some 1,700 People 's Armed Police into Lhasa in February 1989 in an attempt to warn against further disturbance .
Minor clashes had been occurring since 1987 , and when the scale of unrest grew , Hu responded with the deployment of some 1,700 People 's Armed Police into Lhasa in February 1989 in an attempt to warn against further disturbance .