WASHINGTON — The White House Friday defended “tireless” Secretary of State John Kerry, saying his long-odds Middle East peace bid had not been a waste of time because the stakes were so high.

The administration rode to Kerry’s defense amid rising criticism of his decision to devote so much time to the peace effort, which appears on the verge of collapse.

“What Secretary Kerry has done is work tirelessly,” said Josh Earnest, a White House spokesman, noting the top US diplomat’s frequent travel to Israel and the Palestinian territories.

“He’s been tireless in his efforts to try to broker some common ground between the Israelis and Palestinians.”

Asked whether Kerry’s time had been wasted, or if it could have been better spent on many of the other boiling global crises, Earnest said the goal of Middle East peace was so important that he had been right to try.

“The stakes in this situation were very high, … the world would stand to benefit significantly from the peaceful resolution of the differences between the Israeli people and the Palestinian people.”

But Earnest also admitted that the chances of Kerry succeeding when he embarked on his Middle East peace quest a year ago had never been high.

“I don’t know if people in Las Vegas are betting on these kinds of things these days, but I’m sure the odds — if they were … would be very long.”

The White House reiterated Kerry’s position that with the talks apparently on the rocks owing to a disintegration of the already meager trust between Palestinians and the Israelis, it was time for both sides to make tough choices.

Earnest, however, refused to say that Washington had given up on the process.

“That presupposes an additional step here, that at some point somebody throws up their hands and walks away. Secretary Kerry’s certainly not willing to do that.”

Kerry was returning to the United States Friday and Earnest said he would speak to President Barack Obama in the coming days to assess US options.

Kerry spoke to both Israeli and Palestinian leaders on Thursday, trying to bring the two sides back from the brink.

But Palestinian president Mahmud Abbas rejected his appeals to withdraw the applications he signed on Tuesday to adhere to 15 international treaties, a Palestinian official told AFP.

And Israeli Prime Minister Benjamin Netanyahu ignored appeals to refrain from “unhelpful” tit-for-tat moves and asked officials to draw up a range of tough reprisals, Israeli media reported.

Kerry has faced a barrage of unflattering media criticism in the United States in recent days, especially over revelations Washington could offer the release of US born Israeli spy Jonathan Pollard to entice concessions from Israel.

Several mainstream US papers branded the suggestion as “desperate.”