When US Secretary of Defense Ash Carter asked Turkey on Monday to "stay focused" in the fight against the Islamic State (IS) and stop attacking US-backed Kurdish forces, Turkish officials responded with a suggestion of their own.

"Americans should revise their policy of supporting (the Kurdish-led force) at all costs," Turkish presidential spokesperson Ibrahim Kalin said in a Turkish newspaper on Tuesday.

It was the latest rebuke to American damage-control efforts after US-backed Kurdish forces clashed with American NATO ally Turkey over the weekend. The Syrian Kurds blew up a Turkish tank in the north of Syria on Saturday, killing at least one soldier, and Turkish warplanes attacked Syrian Kurds the following day, killing at least 35 people.

Experts on the region say the US has mismanaged its relationships with allies who have wildly differing objectives in Syria. And this, says Robert Ford, the last US ambassador to Syria, has created a quagmire that could have been avoided.

"We managed to make everyone angry at us: The Syrian kurds, the larger Syrian opposition, as well as the Turks," said Ford, who is now a senior fellow at the Middle East Institute.

Ford said this is partly because the US failed to communicate the limits of its support to the Syrian Kurds. Before Turkey launched an unprecedented offensive, code-named "Operation Euphrates Shield," into northern Syria last week. US Vice President Joe Biden visited Turkey and publicly announced that the Kurdish-led Syrian Democratic Forces, or SDF, would need to withdraw to the east of the Euphrates River, as Ankara had requested, or the US would no longer support them.

"If the vice president has to say that in Turkey, there's a problem," Ford said. "That message should have been clear to [the SDF] long before the VP got to Turkey."

The Turks made clear their offensive had two aims: to drive IS militants away from their border with Syria, and to prevent Syrian Kurds from linking together the two autonomous zones under their control in order to create a large, semi-independent statelet in northern Syria. One of Turkey's biggest national security fears is that Syrian Kurdish gains will feed Turkish Kurds' aspirations for an autonomous zone of their own in Turkey's southeast, where the Kurds are engaged in a war against the Turkish government.

'If this undermines the Kurdish will to go after the Islamic State in Syria, then our efforts to combat them will be stalled.'

Ford says he warned President Barack Obama's administration in 2014 and 2015 not to support the Kurds due to the problems it would cause with Turkey and other Syrian opposition groups.

"What we have in the past five days is we are now harvesting something that we started sowing back in early 2015," said Ford, who resigned from the State Department in 2014 due to his disagreement with US Syria policy, particularly its refusal to arm what he said were Syria's moderate rebels.

According to Ford, the Obama administration feared it would violate international law if it armed forces that would in turn attack the government of Syrian president Bashar al-Assad. And the Kurds didn't want to fight Assad, they wanted to fight the Islamic State — with the understanding that they could expand their own territory in the process.

And expand they did. The Kurds grew their territory by 50 percent as they drove off IS militants with help from US air support and advisors. They also lost hundreds of fighters in the process.

So it must have come as a shock to the Kurds when, just a few weeks after they fought a bloody battle to evict IS from the town of Manbij at America's request, Biden showed up in Turkey and said the Kurds would need to withdraw from the town in order to accommodate the Turks, says Joshua Landis, director of the Center for Middle East Studies at the University of Oklahoma.

"Of course the Kurds feel betrayed, and they were betrayed," he said. "I'm sure the US Special Forces who worked with the Kurds over the past two months are feeling very embarrassed, because they feel like they lied through their teeth as they gave encouragement to the Kurds to do the heavy lifting."

The question now, Landis says, is whether this will affect future US plans to use the Kurds as the tip of its anti-Islamic State spear, especially in the battle to take the group's de facto capital, Raqqa. The new US general in charge of the US war against IS has said the US and its allies intend to take Raqqa by next August — and the US is depending on its Kurdish allies to comprise the main ground fighting force in the effort.

Landis points out that the Kurds have no strategic interest in going to Raqqa since it's a Sunni Arab city far east of their territory.

"If this undermines the Kurdish will to go after ISIS, then our efforts to combat ISIS in Syria will be stalled," he said. "[If] the Kurds go back to their tents and sulk, any effort to send them to Raqqa is going to be seriously compromised."