WASHINGTON- Turkey’s president says his country was “hurt deeply’’ by a House resolution that recognized the century-old mass killings of Armenians by Ottoman Turks as genocide.

The move was a clear rebuke to Turkey in the wake of its invasion of northern Syria.

President Recep Tayyip Erdogan says at a White House news conference that the House-passed measure has the potential to cast a “deep shadow over our bilateral relations.”

Historians estimate that up to 1.5 million Armenians were killed around World War I, and many scholars see it as the 20th century’s first genocide. Turkey disputes the description.

Erdogan says decision-makers about an event 104 years ago should be historians, not politicians.

President Donald Trump says Turkey’s purchase of Russian air defense system creates “serious challenges,” but he says he hopes they can be resolved.

NATO-member Turkey angered the U.S. when it bought the S-400 system. The U.S. says the S-400 poses a threat to NATO and U.S. aircraft. The Trump administration responded by kicking Turkey out of the program to help build the F-35 fighter jet.

Trump says he talked about the issue on Wednesday with Turkey’s president, Recep Tayyip Erdogan , and Trump says he’s asked Secretary of State Mike Pompeo and other advisers to work to resolve the problem.

Trump also says he wants to seal a two-way trade agreement with Turkey to increase trade with Turkey to as much as $1 billion.