Turkish President Recep Erdogan has declined an invitation from counterpart Vladimir Putin to attend the ceremony marking the 70th anniversary of Moscow’s victory in World War II, in an apparent diplomatic reprisal against Russian leader’s decision to label the 1915 killings of Ottoman Armenians as genocide last month, the Hürriyet Daily News reports.

Russian diplomatic sources told daily Hürriyet on May 5 that Turkey would be represented by Ambassador Ümit Yardim at the May 9 Victory Day Parade in Moscow.

Upon a question from a Russian journalist, Turkish Parliament Speaker Cemil Çiçek said during his visit to Moscow on April 15 that he “was sure that President [Erdogan] would try come” to Moscow for the ceremony.

“April 24, 1915 is a melancholy date, related to one of the most horrendous and dramatic events in human history, the genocide of the Armenian people,” Putin said in a letter to the World Without Genocide commemorative event on April 23, the text of which was also posted on the Kremlin website.

Furthermore, the Duma voted on April 24 to pass a resolution that described the 1915 events as “genocide.”

Putin and French President François Hollande were among the leaders who joined the commemorations in Armenia’s capital Yerevan on April 24 to mark the 100th anniversary.

After the Turkish Foreign Ministry strongly condemned Putin and the Duma, President Erdogan personally dove into the issue.

“We wish that Mr. Putin and Mr. Hollande had not gone to Armenia [on April 24]. Two heads of states went there [in Yerevan]. Thank God, 20 heads of state came to us,” Erdogan said.

This year Turkey moved its ceremony for the centennial anniversary of its victory at the Battle of Gallipoli to April 24, to coincide with the Yerevan event. In Gallipoli, Erdogan hosted leaders of the World War I Allies, including 21 heads of state, Australian Prime Minister Tony Abbott, New Zealand Premier John Key, as well as the heir to the British throne Prince Charles and his son Harry.

Diplomatic sources in Moscow told Hürriyet that Putin’s invitation was conveyed to Ankara in March, but Putin’s stance over 1915 prompted Turkey to decline it.