Secretary of State John Kerry said on Friday Washington was evaluating whether to continue its role in Middle East peace talks, signaling his patience with the Israelis and Palestinians was running out.

Speaking during a visit to Morocco after a week of setbacks, Kerry said there was a limit to U.S. efforts if the parties themselves were unwilling to move forward.

“This is not an open-ended effort, it never has been. It is reality check time, and we intend to evaluate precisely what the next steps will be,” Kerry said, adding he would return to Washington on Friday to consult with the Obama administration.

U.S. officials say Kerry had been blindsided by recent Israeli and Palestinian moves that had compromised undertakings made when they launched the latest round of talks aimed at ending their enduring conflict last July.

“They say they want to continue, neither party has said they have called it off, but we are not going to sit there indefinitely,” Kerry said, making his bleakest assessment yet of talks that he has dedicated a huge amount of energy to.

The negotiations were catapulted into crisis at the weekend when Israel refused to act on a previously agreed release of Palestinian prisoners unless it had assurances the Palestinians would continue talks beyond an initial end-April deadline.