Turkish prime minister Recep Tayyip Erdogan has offered condolences to the descendants of victims of the mass killing of Armenians by Ottoman troops during World War I.

Mr Erdogan's statement was the first such overt comment by a Turkish leader over the killings, considered by many as the first genocide of the 20th century.

He unexpectedly described the events as "inhumane", using more conciliatory language than has often been used in the past.

It comes on the eve of the 99th anniversary of the start of the mass deportations of Armenians in 1915.

"The incidents of World War I are our shared pain," Mr Erdogan said in a statement.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 21 minutes 23 seconds 21 m Turkish foreign minister Ahmet Davutoglu discusses Armenia

"It is our hope and belief that the peoples of an ancient and unique geography, who share similar customs and manners, will be able to talk to each other about the past with maturity and to remember together their losses in a decent manner.

"And it is with this hope and belief that we wish that the Armenians who lost their lives in the context of the early 20th century rest in peace, and we convey our condolences to their grandchildren."

The statement, released in nine different languages, repeated previous calls for dialogue between the two countries, and the setting up of a historical commission to probe events surrounding the killings.

"Having experienced events which had inhumane consequences - such as relocation - during World War I, should not prevent Turks and Armenians from establishing compassion and mutually humane attitudes among towards one another," Mr Erdogan said.

The exact nature and scale of what happened during fighting that started in 1915 is highly contentious and continues to sour relations between the two countries.

Armenia has been trying to get Turkey to recognise the killings of up to 1.5 million people under the Ottoman empire as genocide.

However, Turkey says 500,000 died of fighting and starvation during World War I and categorically rejects the term genocide.

A photo from the Armenian Genocide Museum-Institute, dated 1915, shows Turkish soldiers standing over what are said to be the skulls of dead Armenian villagers ( AFP/Armenian Genocide Museum-Institute )

AFP