Australia and New Zealand Thursday warned terrorists could target Anzac Day commemorations on the Gallipoli peninsula in Turkey this month, and urged travellers to avoid Ankara and Istanbul.
The emotive event on April 25 remembers the heroism and sacrifice of Australians and New Zealanders during World War I and their campaign against the Ottoman Empire in 1915.
Canberra and Wellington said intelligence suggested it could be targetted by extremists this year.
"The Turkish authorities are taking this extremely seriously. The celebrations on Gallipoli are as important to the Turkish authorities and Turkish people as they are to the Australians," said Veterans' Affairs Minister Dan Tehan.
The warning was echoed by New Zealand Foreign Minister Murray McCully, who called on citizens "to exercise a high degree of vigilance in public places" in Turkey and keep track of security updates.
While Canberra's advice to travellers had not changed from "exercise a high degree of caution" in Gallipoli and Turkey overall, it said they should "reconsider their need to travel to Ankara and Istanbul".
"We are conscious of the effect of this on the many Australians planning to attend this year's Anzac Day commemorations at Gallipoli," Tehan said.
Hundreds of Australians and New Zealanders annually make the trip to Gallipoli to mark the amphibious assaults on the peninsula in what is now western Turkey.
Many were killed in the initial assault and the overall Allied campaign ended in failure and evacuation.
But the spirit shown by the Anzac (Australian and New Zealand Army Corps) troops has long been seen as critical in forging a national identity in New Zealand and Australia. Both commemorate April 25 as Anzac Day.