Israeli President Shimon Peres told US President Barack Obama on Wednesday he was unsure Iraq could be kept together as sectarian violence threatens to tear the country apart.
Peres, on his final foreign trip as president following decades on the world stage, had Oval Office talks and lunch with Obama at the White House.
"The best thing that could happen is that Iraq will remain a united country, but I wonder if it's possible," Peres told reporters after the talks.
The Israeli president also said it was not the outside world's job to mediate divisions between the Shiite and Sunni sects of Islam or to "decide who is the real heir of Mohammed."
Peres also said he and Obama discussed Israel's concerns about the US drive for a deal with Iran over its nuclear program.
The best solution, according to the Israeli president, would be one modeled on the program to dismantle Syria's chemical weapons program, which would involve all components for armaments being taken out of the country.
Peres also likely raised the issue of Jonathan Pollard, a US-born Israeli spy who was arrested in Washington in 1985 and jailed for life.
Washington was reportedly considering releasing Pollard early in exchange for Israeli concessions in the troubled peace process with the Palestinians brokered by the United States, which has since foundered.
The Israeli government said Peres enlisted support in the hunt for three kidnapped Israeli teenagers in the West Bank.
A White House official said Obama and Peres spoke about Israeli-Palestinian talks, Iran, Iraq, and other regional issues.
"President Obama also expressed our deep concern for the three missing Israeli teenagers, one of whom is also an American citizen," the official said.
Peres, who has a friendly relationship with Obama, in comparison to the sometimes tense ties the US leader has had with Prime Minister Benjamin Netanyahu, is due to receive the Congressional Gold Medal in Washington on Thursday.
Peres will be succeeded in the largely ceremonial position as president by Reuven Rivlin, a far-right member of the ruling Likud party next month.