KIEV (REUTERS) - Fifa has apologised to Ukraine for an error during last week's presentation of the 2018 World Cup logo in Moscow, which showed the Crimean peninsula as a part of the Russian Federation.

The incident added tension to relations between the countries after Ukraine's Crimea peninsula was annexed by Russia in March, sparking the ongoing military conflict between Ukrainian government forces and Russian-backed separatists.

The Football Federation of Ukraine published a letter of apology from Fifa on its website.

"Reference is made to the unfortunate incident which happened during the official emblem launch for the 2018 World Cup in Moscow, Russia," Fifa said. "As part of the official emblem launch, the Local Organising Committee commissioned a local creative agency with an art projection on the Bolshoi Theatre as a unique photo and filming opportunity.

"Unfortunately, a map of Russia, showing the Ukrainian region of Crimea as part of Russia, was selected and used during the projection by the local service provider which escaped Fifa's attention when uploading the video footage on our website and YouTube channel.

"Once this unfortunate incident was brought to our attention we immediately removed the short sequence in question. We regret any inconvenience caused by this unfortunate incident and will assure you to be more attentive to the material produced by the third parties in the future."

Ukraine officially approached Fifa and Uefa in August to impose strict sanctions against Russia for letting three Crimean clubs play in the Russian league.

A special working group set up by the football ruling bodies has been struggling to resolve the issue since September.