Mengistu's overthrow in May 1991 caused a number of shifts. With the shifting of forces towards the Western Equatoria offensive and the beginning of the rains, commanders in Upper Nile felt dangerously exposed. At the same time, the Nasir faction noted that Western support for Garang had fallen due to his alliance with the socialist Mengistu; the United States was the only country to respond favorably to the Nasir commanders' call for a separate South, which they interpreted as a sign of support. As thousands of refugees were returned from Ethiopia, the Nasir faction established contact with government forces beginning in July 1991 to arrange for relief supplies through government lines. By May, negotiations had led the government to agree to support the Nasir group against Garang. However, support for an attempt to remove Garang fell among other SPLA commanders, who felt that a coup attempt would further weaken the movement.