HARARE, Zimbabwe — Officials of Zimbabwe's election commission say early voting has started for police and security personnel who will be on duty during the nation's crucial elections on July 31.

The officials acknowledged there was chaos at many voting stations Sunday. Voting materials were not delivered in time for the special vote for service personnel who won't be able to vote on polling day.

At one Harare voting post, police officers waiting in line pushed each other in impatience at long delays. A senior officer was called to quell the jostling police.

Witnesses said that voting had not started at all elsewhere in Harare and provincial centers.

The election commission had said it was ready for early voting and deployed about 9,000 polling stations countrywide in the past two weeks.