President Barack Obama spoke by telephone with Turkish President Tayyip Erdogan to offer his condolences for those killed and wounded in an attack on an Istanbul nightclub on New Year's Eve for which the Islamic State has claimed responsibility.
Obama also welcomed Turkey's efforts to facilitate a nationwide ceasefire in Syria and a return to political negotiations between the Syrian government and the opposition, the White House said in a statement.
Earlier, the Turkish prime minister accused the United States government of supporting terrorism in Syria.
Binali Yildirim made his comments in front of his Justice and Development Party (AKP) parliamentary group in reference to Washington's backing of Kurdish-Syrian militias fighting against the Islamic State terror group in Syria.
He said the Obama administration was supporting terror by trying "to defeat one terrorist group (the IS) with another one," in reference to the Kurdish People's Protection Units (YPG), considered part of the Kurdistan Workers' Party (PKK) by Turkey, which it sees as a terrorist organisation.
The US was openly supplying weapons to the YPG and the Democratic Union Party (PYD) to support terrorism in the country, the minister said.
Yildirim said he hoped the incoming administration of President-elect Donald Trump would change this policy once sworn-in on January 20.
It was time to decide whether to be friends or enemies, Yildirim said, going on to point out Turkey had been a member of NATO for years and was a strategic member of the alliance.
Turkey was the only country truly fighting IS militants, Yildirim said, determining that those participating in the US-led international coalition in the fight against the IS were doing almost nothing.
