Story highlights The U.S. secretary of state addresses reporters in Ankara, Turkey

He talks about the crisis in Syria and ties that Turkey and Israel share with the U.S.

"We want to see them work together to go beyond rhetoric," Kerry says of Israel and Turkey

Turkish Prime Minister Recep Tayyip Erdogan made the remark at a United Nations conference

U.S. Secretary of State John Kerry waded into the thicket of Mideast politics Friday, chiding the Turkish prime minister for a slam on Zionism while touting the ties the United States has with Turkey and Israel -- two once friendly nations now mired in antipathy.

Kerry said he and the Obama administration disagreed with Recep Tayyip Erdogan's remark equating Zionism with crimes against humanity, and he called it "objectionable."

He appeared to be making a reference to the remark in his praise of Mustafa Akarsu , the Turkish guard at the U.S. Embassy in Ankara who died in a February 1 suicide attack.

"Mustafa's tragic death reminds all of us of the common bond we share," Kerry told reporters in a joint news conference in Ankara with Turkish Foreign Minister Ahmet Davutoglu. It "underscores the urgent need to promote a spirit of tolerance that includes all of the public statements made by all leaders."

Kerry said he mentioned Erdogan's speech to the foreign minister and plans to broach it with Erdogan.

"That said, Turkey and Israel are both vital allies," Kerry said. "We want to see them work together to go beyond rhetoric and take concrete steps to change their relationship. I believe it's possible."

The remarks overshadowed the key crisis in the region: the Syrian civil war. Kerry said the United States and Turkey share opposition to the regime of Bashar al-Assad in Syria.

He said that Turkey and the United States believe in a political solution in Syria and that both countries have worked to bring about tough sanctions to reduce money flowing to the Assad government. He cited the Patriot missiles placed on Turkey's border with Syria for security and the country's hosting of tens of thousands of Syrian refugees.

"Minister Davutoglu and I believe there is no legitimacy in a regime that creates atrocities against its own people," Kerry said.

Kerry attended a memorial service for the security guard killed at the embassy last month and described him as a "courageous Turk." The United States, he said, "stands strongly with Turkey, our NATO ally in the fight against terrorism."

The embassy was attacked last month by a man Turkish authorities say belonged to the Marxist Leninist organization known as the Revolutionary People's Liberation Party, or DHKP-C, which the U.S. government and others label a terrorist organization.

As for Erdogan's remarks, a senior State Department official earlier said the comment was "particularly offensive" and "complicates our ability to do all the things we want to do together when we have such a profound disagreement about such an important thing,"

Erdogan appeared at the U.N. Alliance of Civilizations, which works to defuse tensions and promote cooperation between the Muslim and Western worlds.

"It is necessary that we must consider -- just like Zionism, or anti-Semitism, or fascism -- Islamophobia as a crime against humanity," the Turkish prime minister said.

Zionism is the Jewish national liberation movement that led to Israel's founding and is the nation's underpinning. Erdogan's remarks drew a quick rebuke from Israeli Prime Minister Benjamin Netanyahu. But many in the Muslim world harbor notions like Erdogan's about the movement.

"This is a dark and mendacious statement, the likes of which we thought had passed from the world," Netanyahu said.

Israel and Turkey are major U.S. allies in the Middle East. But the once extensive cooperation between Turkey and Israel on trade, tourism and military issues has broken down.

Turkey, a NATO member, has been affected by one of the world's most volatile conflicts -- the Syrian civil war -- and has been a staunch opponent of the Assad regime. Israel has been a longtime friend of the United States and is seen as a pro-U.S. bulwark in the region.

The falling out between Turkey and Israel was hastened by the Israeli commando attack on a ship in a Gaza-bound flotilla three years ago. Turkey has called for an apology for the incident, which resulted in the deaths of eight Turks and one American of Turkish origin.