US Secretary of State John Kerry said Friday he would “evaluate” the next steps in the Middle East peace process with President Barack Obama, warning there are “limits” to Washington’s time.

“There are limits to the amount of time and effort that the United States can spend if the parties themselves are unwilling to take constructive steps in order to be able to move forward,” he said in Rabat, Morocco.

“Both sides say they want to continue. Neither party has said they have called it off. But we are not going to sit there indefinitely. It is not an open-ended effort,” he said, adding that it was “reality check” time.

Kerry said it was regrettable that in the last few days both sides have taken steps that are not helpful in promoting peace and ending the decades-long conflict between the two sides.

The US will “evaluate very carefully exactly where this is and where it might possibly be able to go,” he said.

Kerry plans to return to Washington on Friday after a lengthy trip to Europe and the Middle East.

The statement came a day after peace efforts appeared to implode amid mutual recriminations and what the US termed “unhelpful tit-for-tat measures.”

Up until this point, the State Department has steadfastly maintained that talks were ongoing, though they had reached a “critical stage.”

On Thursday, Kerry spoke to both Palestinian Authority President Mahmoud Abbas and Israeli Prime Minister Benjamin Netanyahu, hours after publicly urging them to make “fundamental decisions to compromise.

“The leaders have to lead, and they have to be able to see a moment when it’s there,” he said.

Negotiations appeared all but dead on Thursday after Israel announced it would not release a final tranche of Arab prisoners agreed to as a precondition for talks in July 2013. Ramallah reportedly responded by issuing a new set of demands that included Israeli recognition of East Jerusalem as capital of a Palestinian state and a full settlement freeze.

Finance Minister Yair Lapid wrote on Facebook Friday that Abbas’s move seemed designed to “blow up the talks,” and questioned whether the Palestinians really wanted peace.

“No Israeli will negotiate for any price,” he wrote.

On Tuesday, Abbas signed agreements to join 15 international treaties, some of which are UN-related. Israel said the move was a breach of the pre-talk conditions.

US officials reportedly indicated that Obama was seeking to have Kerry dial down his engagement with the peace process, which he has intensively shepherded through 8 months of fruitless negotiations.

“A point will come where he has to go out and own the failure,” an official was quoted as saying, adding that Kerry should “lower the volume and see how things unfold” for now.