KABUL (Reuters) — An explosion occurred near a polling station in the southern Afghan city of Kandahar on Saturday just an hour after voters began queuing to cast their vote to elect a new president. The election is the fourth presidential vote since the fall of the Taliban to U.S.-led forces.

A senior provincial government official said three people were injured by the blast. No militant group claimed responsibility for the blast.

About 9.6 mln of Afghanistan’s 34 mln people are registered to vote for one of the 14 candidates at around 5,000 polling centres that are protected by some 100,000 Afghan forces with air support from U.S. forces. However, more than 400 polling centres will remain closed because they are situated in areas under Taliban control. Hundreds more will be closed because of security concerns.

Western security sources and Afghan officials said they had asked local media not to sensationalize threats and attacks, concerned that they could discourage voting.