Turkey's main opposition candidate in upcoming presidential election has questioned why electoral authorities are printing millions of extra ballots.

Ekmeleddin Ihsanoglu said Tuesday international observers noted that about 18 million additional ballot papers for the Aug. 10 vote were being printed and wants to know what safeguards are in place to ensure "they won't get into the wrong hands."

A July 31 interim report by the Organization for Security and Cooperation in Europe, which is sending election observers, notes about 55.8 million voters are registered, including overseas, but the electoral board was printing 73.8 million ballots. It said the decision "lacks a clear legal basis."

The electoral board said the discrepancy arose because ballots were printed in batches.

Prime Minister Recep Tayyip Erdogan is widely expected to win the election.