U.S. Secretary of State John Kerry said on Friday that the United States was dismayed by a comment from Turkey's prime minister likening Zionism to crimes against humanity.
"We not only disagree with it, but we found it objectionable," he said.
Kerry addressed a news conference in Ankara following a meeting with Turkish Foreign Minister Ahmet Davutoglu.
Kerry said the comments from Turkish Prime Minister Recep Tayyip Erdogan undermine the push for peace.
"I believe there is a way forward but it obviously gets more complicated in the aftermath such as that we heard in Vienna," he said.
Kerry said he will also raise his concerns during a meeting with Erdogan.
The Turkish prime minister said during a speech in Vienna this week that Zionism should be viewed as a crime against humanity.
A spokesperson for U.N. chief Ban Ki-moon called the statement unfortunate, hurtful and divisive.
Once-close relations between Turkey and Israel have deteriorated since a deadly 2010 Israeli raid on a Turkish aid ship that was part of a flotilla trying to break Israel's blockade of Gaza. Nine Turks were killed in the raid. Israel says its forces acted in self-defense.