The head of Turkey's Parliament warned the United States against passing an Armenian genocide bill, saying in a letter to the U.S. House speaker that the move would harm bilateral ties, AP quoted his office as saying Sunday. Parliament Speaker Koksal Toptan said in his letter to House Speaker Nancy Pelosi that «it might take decades to heal negative effects of the bill if it passes,» Toptan's office said in a statement. Toptan _ who is elected by the legislative body to chair parliamentary sessions _ is considered neutral toward all political parties. The genocide bill declares the killings of Armenians between 1915 and 1917 a genocide, though it would have no binding effect on the U.S. foreign policy. The U.S. House of Representatives' Foreign Affairs Committee is expected to consider the legislation this week. Toptan's letter said the passing of the bill would be declared by Armenians as a confirmation of their view of the historical dispute. «Then, it will be difficult to control the dynamics triggered by Turkish public reaction,» it said. On Friday, Prime Minister Recep Tayyip Erdogan told U.S. President George W. Bush that the measure would «harm the strategic partnership» between the two countries. Toptan said Armenia did not respond positively to Turkish proposal to establish a commission of historians to examine Turkish and Armenian archives and to share their findings with the public. Armenians say more than 1.5 million Armenians were killed in a systematic genocide in the hands of the Ottomans during the World War I, before modern Turkey was born in 1923. Turkey says the death toll is inflated and that the deaths occurred at a time of civil unrest.