Amid a bitter public fight with Israel's government, President Barack Obama on Friday donned a yarmulke and pitched his nuclear deal with Iran and the case for a Palestinian state directly to US Jews.

Visiting Washington's conservative Adas Israel synagogue, Obama embarked on a Hebrew-sprinkled charm offensive which stressed that US-Israeli relations encompass more than just official links with the Likud government of Prime Minister Benjamin Netanyahu.

Telling the 1,000-plus congregation he was delighted to be "an honorary member of the tribe," Obama said "my commitment to Israel's security is and always will be unshakeable."

"The people of Israel must always know America has its back, and America will always have its back."

Netanyahu has publicly opposed a deal that would curb Iran's nuclear program in return for sanctions relief. The White House views the framework accord as a potential signature foreign policy achievement.

"There will be disagreements on tactics when it comes to how to prevent Iran from getting a nuclear weapon, and that is entirely appropriate and should be fully aired," Obama said.

The president added that he had no interest in reaching a bad deal.

"I'm interested in a deal that blocks every single one of Iran's pathways to a nuclear weapon -- every single path."

"In other words, a deal that makes the world and the region -- including Israel -- more secure. That's how I define a good deal."

Obama also tacitly addressed his split with Netanyahu over the need for a two state solution to resolve the Palestinian-Israeli stalemate.

"I feel a responsibility to speak out honestly about what I think will lead to long-term security and to the preservation of a true democracy in the Jewish homeland," he said to rapturous applause.

"And I believe that's two states for two peoples, Israel and Palestine, living side by side in peace and security. Just as Israelis built a state in their homeland, Palestinians have a right to be a free people on their land, as well."