It's been a confusing couple of weeks for U.S. allies in the Middle East.

White House officials have been making the rounds in the region, reiterating the U.S. administration's signature fierce rhetoric against Iranian geopolitical ambitions.

But the pledges of continued U.S. support directly contradict what's been described as President Donald Trump's isolationist drive, which in its latest manifestation saw the announcement via tweet to withdraw all American troops from Syria — the very theater that officials had previously spotlighted as key to pushing back on Iran.

"You have a tweet from the president about withdrawal of U.S. troops from Syria after months of working together with our allies in the Arab world, with the interagency and State Department, Pentagon," Fred Kempe, president of the Atlantic Council, told CNBC's Hadley Gamble in Abu Dhabi on Saturday. "And suddenly everything's changed with a single tweet."

Trump's December decision drew a barrage of criticism from lawmakers and security experts alike, who warned that the so-called Islamic State was not completely defeated in the war-torn country and that an abrupt departure would be abandoning U.S. local partners on the ground. So Secretary of State Mike Pompeo and national security advisor John Bolton, among others, have been sent to reassure allies of U.S. commitment in the region — but it may be too late to quell their fears.

Pompeo laid out his framing of America's vision for the Middle East during his speech in Cairo on Thursday. "When America retreats, chaos often follows. When we neglect our friends, resentment builds. And when we partner with enemies, they advance," he said.

But the message's divergence from Trump's own policy decision was not lost on observers and allies.

"There's a nervousness — one wants to believe that message," Kempe said. "But I'm hearing from officials in the Middle East more concern about American predictability over time. They want to believe there's this permanent shift on behalf of allies to stand up to Iran, there are a lot of signs that's really there, but they're made nervous by the Syria shift."