Polling stations opened in Zimbabwe Friday morning in a presidential election branded a "sham" by the opposition and the West after opposition leader Morgan Tsvangirai withdrew from the contest, according to DPA. Tsvangirai pulled out of the run-off poll citing fears for the safety of MDC supporters, leaving longtime President Robert Mugabe as the only candidate. Several polling stations in the capital Harare opened shortly after 7 am (0600 GMT) but some had yet to open their doors, witnesses said. Early signs pointed to a low turnout in the capital - an opposition stronghold - with only a handful of voters waiting to cast their vote at most polling stations visited by a Deutsche Presse-Agentur dpa correspondent. Several million Zimbabweans are registered to vote at around 1,962 polling stations nationwide. Tsvangirai and the US ambassador to Zimbabwe, James McGee, have accused Mugabe of deploying the military and militia to "frogmarch" voters to the polls in an attempt to produce a large turnout. In Harare some people expressed fears their thumbs would be checked for the indelible red ink that proves they voted, according to DPA. Tsvangirai withdrew from the contest over a spate of state-sponsored militia attacks on MDC supporters since the first round of voting for president on March 29, in which Tsvangirai took more votes than Mugabe but not enough for an outright victory. The MDC says around 90 of its supporters have been killed, DPA reported.