RAMALLAH, West Bank: A mounting rebellion by Hamas leaders in Gaza against a breakthrough power-sharing agreement with Palestinian President Mahmoud Abbas highlights a potentially fatal flaw - the deal never spelled out how the Western-backed leader can take charge again in Gaza, the territory he lost to a violent takeover by the Islamic militants.

Former bitter foes Abbas and Khaled Mashaal, Hamas' top leader in exile, signed the Qatar-brokered deal in Doha last week, saying they are committed to a true partnership. As part of the agreement, Abbas is to head an interim unity government that replaces rival administrations in the West Bank and Gaza and leads the Palestinians to general elections.

Abbas needs to strike a delicate balance to make it work.

The Palestinian leader has to satisfy international demands that the interim government - to consist of politically independent technocrats - not be a front for Hamas, shunned by the West as a terror group. If it is seen as too close to Hamas, the Palestinians would likely lose hundreds of millions of dollars in Western aid.

At the same time, he risks sabotage from Hamas leaders in Gaza if he tries to strip them of too much of their power. In the nearly five years it ruled the territory, Hamas hired some 40,000 civil servants and security forces, many of them supporters of the movement, while 62,000 troops and civil servants forced out by the 2007 takeover - many of them pro-Abbas - are waiting to return to their old government jobs.

Gaza leaders of Hamas have voiced their misgivings in increasingly strident tones. The Hamas bloc of legislators last week said the deal is illegal because Abbas cannot serve as both president and prime minister.

On Saturday, the Hamas strongman in Gaza, Mahmoud Zahar, complained that Mashaal did not consult with other leaders in the movement before signing the deal and that the decision-making Shura Council should meet to correct what he termed a mistake.

"We feel there is a real crisis concerning the Doha agreement, and that this problem should be resolved within the institutions of the movement," he said in comments published by the Egyptian news agency MENA.

Across the board, Hamas lawmakers in the Abbas-run West Bank rushed Sunday to support the agreement, siding with Mashaal against the Gaza rebels. "Reconciliation is our strategic choice and we should go for it without hesitation." said Hamas legislator Mona Mansour.

Such public airing of disagreements is rare for tightly organized Hamas, a Gaza offshoot of the Muslim Brotherhood, the pan-Arab movement that scored post-Arab Spring election victories in Egypt and Tunisia.

It is still unclear whether the internal dispute is only about protecting Hamas' interests in Gaza or also the change in direction recently advocated by Mashaal.

The unity deal, first reached in principle last year, was made possible by a narrowing of the political differences between Hamas and Abbas, said Mustafa Barghouti, an independent from the West Bank who has played a key role in reconciliation.

Mashaal, while not formally renouncing violence, has embraced the idea of "popular protests" against Israeli occupation as a gesture to Abbas, Barghouti said. And while Hamas has long opposed Abbas' talks with Israel on the terms of a Palestinian state, Abbas now seems to have given up hope he can reach a deal with the current rightist Israeli government.

"There is no political reason for a division," said Barghouti.

In the latest sign of Abbas' pessimism about negotiations with Israel, he told the Arab League on Sunday that he sees no point in resuming last month's low-level border talks unless the Jewish state freezes settlement building.

Israel, which has refused to halt construction, has condemned the reconciliation.

A text message statement from the office of Israeli Prime Minister Benjamin Netanyahu said that Abbas' insistence on a settlement freeze meant he was "turning his back to peace."

"Instead of entering a negotiation that will bring an end to the conflict, (Abbas) prefers to align himself with the Hamas terror group, the same Hamas that embraces iran," it said.

Progress on reconciliation has been slow, a sign of continued distrust.

Hamas complained that West Bank security forces loyal to Fatah have reneged on promises to release dozens of Hamas prisoners, and that only a few were freed. Election officials say that in apparent retaliation, Hamas in Gaza prevented them from trying to update voter records ahead of the planned votes for president and parliament.

Following last week's agreement, Abbas is to put together his transition government. He says however he does not want to announce the composition of his government until he is sure he can hold elections - a task complicated by ensuring his elections commission can work in Gaza and in Israeli-annexed east Jerusalem.

Once a unity government is in place, Abbas' biggest challenge would be to establish a single security service out of two rival forces. In the West Bank, many of Abbas' forces have undergone training by the U.S. and have cooperated with Israel in reining in Hamas, while the Hamas government in Gaza, with a force of 18,000, receives funding from iran.

Last year's initial unity deal called for a gradual blending of the security forces, but did not say how much of that would take place before general elections. However, the West might balk if troops closely linked to Hamas continue to control Gaza.

Abbas might also be held responsible by Israel if smaller militant groups tolerated by Hamas continue to fire rockets from Gaza at Israel from time to time. In recent years, Israel has praised the level of security cooperation it has received Abbas in the West Bank, and a loss of a good working relationship with Israel could make it very difficult to run a Palestinian entity that is still very dependent on its neighbor.

The delicate reconciliation arrangements seem to require an extraordinary amount of good will from Hamas leaders in Gaza - and that seems in short supply.