Turkey's Prime Minister Ahmet Davutoglu paid homage Thursday to the "heroism" of Allied troops who lost to forces of the Ottoman Empire 100 years ago at the battle of Gallipoli.

"It was an epic achievement by your ancestors and ours a hundred years ago that has not been forgotten," Davutoglu said at a symbolic "summit for peace" in Istanbul to mark the start of the conflict in April 1915.

The Armenian Church on Thursday conferred sainthood on some 1.5 million Armenians massacred by Ottoman forces a century ago, as tensions raged over Turkey's refusal to recognize the killings as genocide.

The ceremony, which is believed to be the biggest canonization service in history, came ahead of commemorations expected to see millions of people including heads of state on Friday mark 100 years since the start of the killings.

Austrian lawmakers' decision to condemn as "genocide" the massacre of Armenians by Ottoman Turks during World War I will have "unfavorable repercussions" on Turkish-Austrian relations, Turkish Foreign Minister Mevlut Cavusoglu said on Thursday.

"The adoption of this declaration will inevitably have unfavorable repercussions on bilateral relations," he told his Austrian counterpart Sebastian Kurz by telephone, the Turkish foreign ministry said in a statement.

Maronite Patriarch Beshara al-Rahi has urged the international community to recognize the Armenian genocide, expressing fears of further such atrocities against Christians in the world.

Al-Rahi, who is in Armenia to attend the ceremony to mark the centenary of the World War I killings by Ottoman Turks, was quoted by the National News Agency as saying on Thursday that “the international community and people with goodwill should recognize the genocide.”

Turkey on Wednesday stopped Bosnian Serb leader Milorad Dodik's plane from flying over its territory, preventing him from attending a ceremony to mark the centenary of the Armenian genocide, his cabinet said.

"Although all authorizations for this flight had been initially obtained, Turkish authorities did not allow the flight over their territory," Dodik's cabinet said in a statement.

Turkish leaders on Wednesday expressed satisfaction that the United States appeared to be holding off from describing the mass killings of Armenians in the Ottoman Empire as genocide, ahead of the 100th anniversary of the tragedy.

One of Turkey's worst nightmares is that President Barack Obama would acknowledge the killings as a genocide on the April 24 anniversary but comments by U.S. officials have indicated that this will not be the case.

Council of Europe chief Thorbjoern Jagland on Wednesday urged Armenia and Turkey to reestablish relations, speaking in Yerevan ahead of the 100th anniversary of the Armenian genocide.

"If there is a chance of returning to the 2009 protocols, establishing diplomatic relations, I urge both sides to seize it," the head of the pan-European body said at an international forum ahead of the genocide anniversary on Friday.

Turkish President Recep Tayyip Erdogan on Wednesday accused EU states of leaving migrants "to their deaths" after a succession of deadly disasters that have cost hundreds of lives.

His comments came as European governments, under mounting pressure to act decisively on the growing Mediterranean migrant crisis, were to hold an emergency summit on the issue Thursday.

A Turkish student was handed a suspended one-year prison sentence for "insulting" a local governor by retweeting a satirical article, as concerns grow over the state of freedom of expression in Turkey, reports said Wednesday. 

The sentence was the latest in a string of actions to prevent criticism on Twitter of Turkish officials and President Recep Tayyip Erdogan.

Turkish President Recep Tayyip Erdogan on Wednesday launched one of his strongest attacks yet against Islamic State (IS) jihadists, saying the group was a "virus" working to destroy the Muslim community.

Ankara has been repeatedly criticized in recent months for not doing enough to halt the advance of IS to its borders, but Erdogan said after meeting Iraqi President Fuad Masum that the group had to be confronted.