ROME — As the United States grapples with some of the most intractable problems in the Middle East, it has run into a buzz saw of criticism, not from traditional enemies but from two of its strongest allies.

During stops in Paris and London this week, Secretary of State John Kerry found himself insisting that the United States was not facing a growing rift with oil-rich Saudi Arabia, whose emissaries have described strains over U.S. policy on Egypt, Iran and Syria.

And during a stop in Rome, Kerry sought to reassure Prime Minister Benjamin Netanyahu of Israel that the Obama administration would not drop its guard in the newly invigorated nuclear talks with Iran.

Kerry’s comments appeared to do little to convince Netanyahu, whose demands that Iran dismantle its nuclear program seem to go well beyond any compromise that the United States and other world powers are prepared to explore.

But the criticism by Saudi officials has been the most vehement, as they have waged a campaign against the United States’ policy in the Middle East in private comments to diplomats and reporters, as well as in public remarks by a former intelligence official.

Saudi officials have made it clear they are frustrated with the Obama administration — not just for its reluctance to do more to aid the rebels fighting Syrian President Bashar Assad, and not just for its willingness to engage Iran in negotiations, but also for its refusal to endorse the Egyptian military’s ouster of President Mohammed Morsi and the crackdown on Morsi’s Muslim Brotherhood party.

Some Middle East experts said that the unease over U.S. policy went beyond the details of the United States’ position on Syria or a potential nuclear deal with Iran. It is also fueled, they say, by the perception that a bedrock principle of the Obama administration’s policy is the desire to avoid diplomatic and especially military confrontations in the Middle East.

“There is a lot of confusion and lack of clarity amongst U.S. allies in the Middle East regarding Washington’s true intentions and ultimate objectives,” said Robert Danin, a senior fellow at the Council on Foreign Relations. “There is also widespread unease throughout the Middle East, shared by many U.S. allies, that the United States’ primary objectives when it comes to Iran, Egypt or Syria are to avoid serious confrontation.”