U.S. Secretary of State John Kerry on Friday, March 1, criticized a comment by Turkey's Prime Minister likening Zionism to crimes against humanity in a disagreement that cast a shadow over talks between the NATO allies, Reuters reported.

Kerry, on his first trip to a Muslim nation since taking office, met Turkish leaders for talks meant to focus on the civil war in neighboring Syria and bilateral interests from energy security and Iran's nuclear program to counter-terrorism.

But the comment by Turkish Prime Minister Tayyip Erdogan at a UN meeting in Vienna this week, condemned by his Israeli counterpart, the White House and UN Secretary-General Ban Ki-moon, has clouded his visit.

"We not only disagree with it, we found it objectionable," Kerry told a news conference with Turkish Foreign Minister Ahmet Davutoglu, saying he raised the issue "very directly" with Davutoglu and would do so with Erdogan.

Erdogan told the UN Alliance of Civilizations meeting in Vienna on Wednesday: "Just as with Zionism, anti-Semitism and fascism, it has become necessary to view Islamophobia as a crime against humanity."

The Turkish prime minister's caustic rhetoric on Israel has in the past won applause from conservative supporters at home but raised increasing concern among Western allies.

Kerry said Turkey and Israel were both key U.S. allies and urged them to restore closer ties.

"Given the many challenges that the neighborhood faces, it is essential that both Turkey and Israel find a way to take steps ... to rekindle their historic cooperation," Kerry said. "I think that's possible but obviously we have to get beyond the kind of rhetoric that we've just seen recently."

After Kerry and Erdogan met, a senior U.S. State Department official said that the secretary of state "had a respectful but frank discussion of the (prime minister's) speech in Vienna, and how to move forward. The Secretary made U.S. concerns very clear."

The official said the two sides also discussed Middle East peace, Iran, Iraq, Syria, Gulf security and how to deepen their economic relations.