CAIRO - The chairman of Egypt's main state wheat buyer said on Thursday he hoped Russia would honour existing wheat contracts after Moscow said it would temporarily ban grain exports from the drought-wracked country. "If a decision is issued and it is an official decision the Russian government has to ... allow (buyers) to implement the contracts that have been completed, then ban any other contracts after August 15," Nomani Nomani, chairman of Egypt's General Authority for Supply Commodities, told Reuters. "The Russian government has the right to take any decision that suits it," Nomani added. Egypt is the world's largest wheat importer. GASC has signed contracts for the purchase of 540,000 tonnes of wheat from Russia for delivery between August 1 and September 10.