ANKARA, Turkey (AP) — Turkish President Recep Tayyip Erdogan on Tuesday expressed concerns to German Chancellor Angela Merkel over plans in Germany's parliament to recognize the World War I killings of Armenians as genocide.

Historians estimate that up to 1.5 million Armenians were killed by Ottoman Turks around the time of World War I, an event widely viewed by scholars as the first genocide of the 20th century. 

Turkey however denies that the deaths constituted genocide, and says the toll has been inflated, and that those killed were victims of civil war and unrest.

Germany's parliament will hold a vote on a motion describing the deaths as genocide on Thursday.

Erdogan's office said the Turkish leader told Merkel during a telephone conversation that it was "important that a prudent approach is displayed." His office said Erdogan had initiated the call.

Before departing for a trip to Uganda and Kenya, Erdogan noted that Germany is home to a large population of ethnic Turks and suggested that ties between the two NATO allies could suffer.

"This situation would of course damage the diplomatic, economic, commercial, political and military ... relations between the two countries," Erdogan told reporters. "I believe that this will be thought through."

The Turkish leader added that any decision taken by the German parliament would not "have any aspect that would be binding under international law."

In Berlin, Foreign Minister Frank-Walter Steinmeier said Turks in Germany were unlikely to change their view of Germany because of the resolution.

"The fact that an event happened 100 years ago isn't an obstacle to Parliament dealing with it," Steinmeier told reporters.

"What's still urgently necessary is a reappraisal of this event from different perspectives, which is certainly not going to be easy and would likely be controversial, by the two neighboring countries," he said, in reference to Turkey and Armenia.