WASHINGTON • It was only an abstention but it was a long time coming. With just weeks left in office, US President Barack Obama finally gave vent to his frustration with Israel.

The White House said Mr Obama had decided to allow the United Nations Security Council to pass a motion condemning Israeli settlement building just hours before the vote.

But officials confirmed that they had been watching draft resolutions in circulation for at least a year and were ready to take a stand when one made it to the table.

Critics of Mr Obama's Middle East policy allege that he has long been trying to engineer an opportunity to isolate Israeli Prime Minister Benjamin Netanyahu.

But White House aides insist that they had simply run out of ways to convince Israel that its building on Palestinian land is sabotaging hopes for peace.

Either way, Friday's UN vote will stand as the final word from Mr Obama before Mr Donald Trump takes power on Jan 20.

"Prime Minister Netanyahu had the opportunity to pursue policies that would have led to a different outcome today," Obama adviser Ben Rhodes said.

For months, Washington has been warning in increasingly strident tones that Israel's accelerating settlement programme is destroying hopes for a two-state peace deal.

Still, Mr Obama's nod for the abstention came under withering criticism, with both Democrats and Republicans accusing him of colluding with a biased world body to betray an ally.

There are suggestions that Mr Obama's decision, made while he was on a Christmas break in Hawaii, had as much to do with his bad blood with Mr Netanyahu as with diplomacy.

Mr Jonathan Schanzer, vice- president of the Foundation for Defence of Democracies, a Washington think-tank, dubbed the relationship a "grudge match".

Mr Netanyahu made no secret of his friendship with Mr Oba- ma's 2012 election rival, Mr Mitt Romney, and last year broke protocol to go behind Mr Obama's back and address Congress to oppose the Iran nuclear deal.

Mr Schanzer suggested that, had Mrs Hillary Clinton won the presidential election, Mr Obama might not have decided to abstain. But, faced with an incoming Trump presidency that may support settlement building, he opted for a binding vote that will weaken Israel's position in any future peace talks.

"You can't unring this bell," Mr Schanzer said.

AGENCE FRANCE-PRESSE