Zimbabwe lifted a paralyzing security net on townships near the southern city of Bulawayo amid charges that the clampdown had been politically motivated. A spokesman in Harare, the African nation's capital, said the operation--fourth in three years--was a temporary measure aimed at lessening political violence. However, Joshua Nkomo, leader of the opposition Zimbabwe African People's Union, termed the security operation "a way of demoralizing the people . . . before elections so they will vote for the government."