JERUSALEM -- President Barack Obama kicked off a trip to the Mideast on Wednesday with his first visit to Israel as president, meeting with Prime Minister Benjamin Netanyahu and projecting a nearly united front on threats posed by Syria’s ongoing civil war and Iran’s nuclear weapons ambitions.

The two men appeared chummy during the visit, joking easily and saluting one another in a sharp departure from the often frosty rapport they’ve exhibited in the past. They met privately at Netanyahu’s residence, then again over a working dinner into the evening, with reports of a chemical weapon attack in Syria and continued fears of Iran’s nuclear program topping their agenda.

On Syria, Obama said the U.S. is investigating reports of a chemical attack this week, but he was not yet ready to confirm whether it had occurred or whether it had been launched by the government as rebels said or as Israel said it had confirmed.

But Obama dismissed the thought that the rebels could have done so – as the regime has charged – and warned that the use of chemical weapons would be a “game changer.” The administration has resisted efforts to intervene military in Syria and Obama wouldn’t say what action the administration would take if it finds chemical weapons had been used.

But, he said, he believed once “you let that genie out of the bottle, then you’re looking potentially at even more horrific scenes than we have already seen in Syria, and the international community has to act on that additional information.”

Israel fears the regime’s considerable cache of weapons could fall into the hands of its enemies, and Netanyahu said he believes the best way to prevent that was to work with the U.S.

The remarks came at a press conference midway through a round of talks between the two leaders that also included the possibility of restarting peace talks between the Israelis and the Palestinians. Obama said he arrived without a specific plan because he wanted to “spend some time listening.”

On Iran, Netanyahu said he’s “absolutely convinced” that Obama is determined to prevent Iran from securing a nuclear weapon and said the two share a similar assessment of Iran’s capabilities – that it could produce a nuclear weapon in about a year. Netanyahu had warned at the United Nations last fall that Iran could need just six months.

Netanyahu maintained that Israel has the right to defend itself, without approval from the United States, and Obama agreed.

“There is not a lot of daylight between our countries’ assessments in terms of where Iran is right now,” Obama said, before adding that “each country has to make its own decisions when it comes to the awesome decision to engage in any kind of military action. And Israel is differently situated than the United States.”

Obama has resisted a push for confrontation and decried saber rattling, saying he believes there is time for sanctions and diplomacy to work and convince the regime in Teheran – which denies it’s pursuing nuclear weapons – to give up its quest.

Obama’s trip, which also will include stops in the West Bank and Jordan, is aimed partly at shoring up his standing among skeptical Israelis. He earned an early round of applause, telling attendees at a red carpet arrival ceremony at the airport in Tel Aviv in Hebrew that it was “good to be back in the land of Israel."