(Reuters) -Russian President Vladimir Putin on Friday denied Moscow was preventing Ukrainian ports from exporting grain and said the best solution would be to ship it through Belarus, as long as sanctions on that country were lifted.

       Putin, saying reports of a Russian export ban were "a bluff", told national television that Western nations were trying to cover up their own policy mistakes by blaming Russia for problems on the global food market.

       Russia's army has seized much of Ukraine's southern coastline and its warships control access to the country's Black Sea ports. Moscow has blamed Ukraine and the West for the resulting disruption of Ukrainian grain exports.

       "If someone wants to solve the problem of exporting Ukrainian grain - please, the easiest way is through Belarus. No one is stopping it," Putin said. "But for this you have to lift sanctions from Belarus."

       Earlier on Friday, Belarus leader Alexander Lukashenko said Minsk was ready to allow the transit of Ukraine's grain to German, Polish, Baltic or Russian ports via its territory if in return it was allowed to ship Belarusian goods from those ports.

       Putin said problems on global food markets were set to worsen because of British and U.S. sanctions on Russian fertilisers.

       (Reporting by ReutersEditing by Chris Reese and Barbara Lewis)