The shock waves from Donald Trump’s surprise announcement that US troops in northern Syria would step aside and allow a Turkish offensive to obliterate its long-term Kurdish partners rippled out of Washington and shook America’s allies across the region.

From Israel to the Gulf, officials, diplomats and commentators expressed fears – in private and in public – that the Trump administration would ultimately prioritise isolationism over loyalty to all his regional partners.

Allies could not only be cast haphazardly to the side, but they could be set up. The Kurdish-dominated Syrian Democratic Forces (SDF), who fought America’s war against Isis, had agreed to Washington’s demands to dismantle some defensive positions along the border with Turkey, ultimately leaving them as exposed when some US troops pulled back.

Even Saudi analysts writing for the usually carefully-worded pan-Arab newspaper Asharq al-Awsat, spoke of the “the state of confusion and emptiness” in US relations.

On Tuesday, under the headline “The flaw in Trump’s foreign strategy” commentator Yousef El-Dini wrote of the president’s “confusing... ego doctrine” where he lashes out and makes bizarre decisions on his own. El-Dini warned of “the vacuum and uncertainty under Trump”.

A US soldier sits atop an armoured vehicle during a demonstration by Syrian Kurds against Turkish threats (AFP/Getty) (AFP)

In Kuwait, Abdullah al-Shayji, an MP, was more acerbic.

“He threw them under the bus,” he wrote in a flurry of energetic Tweets condemning Mr Trump’s decision. “This is how America gives up its allies who fought Isis: Another bitter lesson for all America’s allies!”

Arguably the most worried was Israel, one the US’s most strategic allies in the region. US-Israel relations have been watertight since Trump took office and made a slew of controversial decisions that pleased Israel, including recognising Jerusalem as the country’s capital.

But on Monday, Israeli media revealed that its officials were blindsided by the fact they had not been informed or consulted by the Trump administration about such a drastic move, despite the close intelligence-sharing cooperation they enjoy.

While Israeli prime minister Benjamin Netanyahu kept diplomatically quiet on the matter, Israeli MP, and former education minister, Naftali Bennett went as far as to say a prayer for the Kurdish people on Twitter.

He added: “The lesson for Israel is simple. Israel will ALWAYS defend itself by itself.”

From across the political spectrum, the headlines echoed Mr Bennett’s message.

“Kurds did their job and now they can go to hell, as far as Trump is concerned,” journalist Zvi Bar’el wrote in a frankly worded piece for left-leaning Haaretz.

He argued that the decision reinforced the view that “Washington has no friends in the Middle East, and that any alliances still in force might be reconsidered at any moment and are at risk of being unilaterally annulled.”

Herb Keinon, in right-wing Jerusalem Post agreed saying that the decision cannot be seen “in isolation”.

“After Trump abandons Kurds, Israel knows it can’t rely on anyone.”

Turkey’s president Recep Tayyip Erdogan speaks a press conference (AFP/Getty)

Amos Harel, an Israeli security and defence expert who spoke to numerous officials said: “Everybody I talked to both, on duty and already ready out of the system, agreed this is bad news for Israel and the region.”

He added that instead, the broader message of American isolationism had been received loud and clear.

“They are concerned by Trump’s policy at large and the persona. He doesn’t listen to advice. He doesn’t acknowledge the facts and the intelligence, he works on impulse and is isolationist.”

“How can we depend on Trump in the long term?” he asked.

In Egypt, a country which receives millions of dollars in US military and economic aid every year, newspapers stuck to quoting the uproar emanating from the US.

But Egyptian analyst Timothy Kaldas, a non-resident fellow at the Tahrir Institute for Middle East Policy, said behind closed doors it would be worrying many.

“It reflected a broader trend of Trump not valuing allies while being generally unreliable,” he told The Independent.