Turkey’s president has lashed out at country leaders who have recognized the killings of Armenians by Ottoman Turks as genocide on the centenary of the massacres.

Recep Tayyip Erdogan on Saturday accused France, Germany, Russia and Austria — whose leaders or parliaments recently described the killings as genocide — of supporting “claims constructed on Armenian lies.” He accused the United States of siding with Armenia although President Barack Obama stopped short of using the term in his annual message.

Erdogan said: “They should first, one-by-one, clean the stains on their own histories.”

Historians estimate that up to 1.5 million Armenians were killed in what is widely viewed as the first genocide of the 20th century. Turkey denies that the deaths constituted genocide