The Obama administration is reassessing a year-long effort to broker peace between Israel and the Palestinians in light of “unhelpful” actions by both sides this week, Secretary of State John F. Kerry warned Friday.

“It’s reality-check time,” Kerry said.

Kerry said he would return to the United States on Friday after 13 days on the road that included an emergency rescue mission to Jerusalem to try to salvage his signature diplomatic effort. He will consult with the White House about what to do next, Kerry said.

Days of tit-for-tat diplomatic maneuvers by Israeli and Palestinian leaders left negotiations in tatters and the chief U.S. diplomat little choice but to declare a time-out.

“There are limits in 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,” Kerry said in Morocco, the last stop on a trip that hop-scotched from Europe to the Middle East and North Africa.

Talks Kerry launched last summer after months of wheedling appeared all but dead Friday, although Kerry said both sides have told American envoys that they would like to continue.

Palestinian and Israeli negotiators had pledged to Kerry to stay at the table through the end of this month. Absent an outright rupture or a breakthrough, the U.S.-backed effort appears likely to end then. Kerry was trying for an agreement to extend talks this week that included significant sweeteners for both sides.

“This is not an open-ended effort,” Kerry said. “It never has been.”

Each side is blaming the other for the impasse. A meeting of top negotiators and chief U.S. Mideast envoy Martin Indyk devolved into a shouting match early Thursday. Kerry’s phone appeals to Israeli Prime Minister Benjamin Netanyahu and Palestinian Authority President Mahmoud Abbas later Thursday had no apparent effect.

“Neither party has said they have called it off, but we are not going to sit there indefinitely,” Kerry said. His businesslike tone and bleak assessment were a contrast to previous, mostly upbeat, public remarks about the prospects for further talks.

The goal is an independent Palestinian state alongside Israel, and a lasting peace treaty. The effort is the most ambitious in six years, and has drawn Kerry and U.S. negotiators deep into the details of borders, security arrangements and the disputed status of Jerusalem.

Israel says that the Palestinians created the crisis by signing documents to become party to 15 United Nations conventions and protocols — treaties that seek to protect the rights of women, children, the disabled and civilians in times of war and conflict.

The Palestinians say they signed the treaties only because the Israelis had broken their promise, made in July, to release 104 Palestinian prisoners.

The Israelis balked at freeing the final batch of 26 prisoners because they said they were in American-led negotiations with the Palestinians to extend the talks.

A senior Palestinian official, Nabil Shaath, told Reuters that Abbas’s surprise announcement Tuesday that he was resuming efforts at the U.N. was intended only to spotlight Israel’s failure to release the prisoners. Kerry canceled a planned trip to the West Bank to see Abbas on Wednesday because of the announcement.

“We have not abandoned the process,” Shaath said. “We will continue these negotiations as we agreed, and I wish for once that America’s patience runs out — with Israel and not the Palestinians,” Shaath said. He said he expects Kerry to reschedule the trip soon.

Israel’s centrist finance minister, Yair Lapid, whose party joined Netanyahu’s government on the condition Israel enter into negotiations with the Palestinians, questioned whether Abbas wanted a deal.

The Palestinian leader “should know that at this point in time his demands are working against him,” Lapid said. “No Israeli will negotiate with him at any price.”

Michael Herzog, a retired Israeli general serving as a consultant to the negotiations, said Friday that the move by Abbas to return to the United Nations for greater recognition “deepened the crisis.”

Mohammed Shtayyeh, who resigned as chief Palestinian negotiator in November over frustration with continued construction of Jewish settlements in the West Bank, told the Israeli newspaper Haaretz, “What’s important to Netanyahu is to preserve his coalition and not to reach an agreement.”

Israelis close to the negotiations say that the final release of prisoners was contingent on “sustained, uninterrupted negotiations.” The same advisers said that the Palestinians were looking for an excuse to break off talks.

Nonsense, said the Palestinians.

“Since Israel failed to release the last group of prisoners, the State of Palestine is no longer obliged to postpone its rights to accede to multilateral treaties and conventions,” the Palestine Liberation Organization’s Negotiations Affairs Department said in a statement.

“What the Israelis have done is to connect the release of the prisoners with continuing of negotiations, and this was something not in the original agreement,” said George Giacaman, political science professor at Birzeit University in Ramallah. “And that is precisely the problem.”

Israeli officials have complained that the Palestinians kept adding new demands.

The Palestinians said the Israelis would never talk about substantive issues — such as borders for a future Palestinian state and whether East Jerusalem would be its capital.

Diana Buttu, a Palestinian analyst and former legal adviser to the Palestinian negotiating team, said that when the Israelis did not release the last batch of prisoners, Abbas was forced to do something, and that the Americans and Israelis, rather than being surprised about the move toward the United Nations, knew the Palestinian leader had to act.

“The reason it broke down this time is that Abbas has to appeal to his domestic constituency,” Buttu said.

Many Palestinians and Israelis have come to the conclusion that the crisis in talks is a manufactured one — that after eight months of talking, the two sides are no closer to a deal than when they started, and that despite their feelings of goodwill for Kerry’s efforts, the talks have failed.

“In my opinion, it was obvious from the beginning that most likely the negotiations would not achieve anything,” Giacaman said. “If they do continue, as they very well might, they will not achieve anything. It will simply be a way to manage the conflict.”

As they wrangled over blame, both sides also contemplated their next moves.

Ynet news in Israel reported that Economy Minister Naftali Bennett said Friday that if the Palestinians took a war crimes case against Israel to the International Criminal Court in The Hague, then Jerusalem would respond with its own charges of war crimes against the Palestinians for firing rockets from Gaza at civilian populations.

Ruth Eglash in Jerusalem contributed to this report.