Secretary of State John Kerry and other administration officials warned of limits to U.S. patience in helping facilitate the Mideast peace process after Israel and the Palestinians signaled an unwillingness to make the concessions necessary to move forward.

Kerry, while traveling in Morocco Friday, said it is now “reality-check time” in determining how much more effort he would dedicate to the talks.

“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.

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

White House spokesman Josh Earnest said Kerry will return to Washington Friday after spending the week traveling to Europe and the Middle East, and will evaluate the U.S. role in the peace process with President Obama.

“There's no doubt that we have reached a point where Palestinians leaders and Israeli leaders need to spend some time thinking about their commitment to taking some very difficult steps,” he said.

Earnest noted, however, that the U.S. has not given up on the process entirely, and both sides have indicated that they would like to continue negotiations.

“We remain committed to the task,” he said, noting that Kerry has made 11 trips to the region to work on the peace process over the last year. This week, Kerry made an emergency visit to Jerusalem to try to salvage the negotiations.

“Secretary Kerry has played a very important role in trying to facilitate conversations between the Palestinians and the Israelis,” Earnest said. “He was doing that not because it was obvious that an agreement could be struck… It's been very difficult for generations for the Israelis and the Palestinians to resolve their differences and he has worked tirelessly on the issue.”

Israel contends that the Palestinians threatened the talks by signing documents to become party to 15 United Nations conventions and protocols – treaties that seek a recognition of their sovereignty that would provide protections to women, children and civilians in war and combat.

The Palestinians counter that they signed the treaties because the Israelis broke their promise to release a fourth batch of Palestinian prisoners, whom Israel considers to be terrorists.