WASHINGTON, Sept 2 (Reuters) - Israeli and Palestinian leaders agreed to a series of direct talks on Thursday, seeking to forge the framework for a US-backed peace deal within a year and end a conflict that has boiled for six decades.

US Secretary of State Hillary Clinton, who hosted the first session of talks between Israeli Prime Minister Benjamin Netanyahu and Palestinian President Mahmoud Abbas, expressed confidence that this effort could succeed where so many others have failed.

President Barack Obama, aiming to resolve one of the world's most intractable disputes, has set a goal of striking a deal within 12 months to create an independent Palestinian state that exists peacefully, side-by-side with the Jewish state.

This will not be easy, Netanyahu said. A true peace, a lasting peace, would be achieved only with mutual and painful concessions from both sides.

Despite widespread skepticism about the chances of this latest attempt to bring peace to the region and the shooting of Jewish settlers by Hamas militants in the West Bank this week, Netanyahu and Abbas agreed to meet again on Sept. 14-15 with Clinton also present.

Diplomats said that meeting will take place in Egypt, which with Jordan is a key Arab backer of the current peace push.

The two sides agreed to meet every two weeks thereafter, US Middle East peace envoy George Mitchell said. The agreement to continue talks marked a small step forward, although a dispute over Jewish settlements on occupied West Bank land could halt progress in its tracks.

We are convinced that if you move forward in good faith and do not waver in your commitment to succeed on behalf of your people, we can resolve all of the core issues within one year, Clinton told Netanyahu and Abbas as the talks began.

You have the opportunity to end this conflict and the decades of enmity between your peoples once and for all. The two leaders, who appeared to be developing some rapport, shook hands after the formal start of the talks in an ornate State Department reception room, marking the resumption of direct dialogue that last broke off in 2008.

Both Netanyahu and Abbas have said they want a two-state solution. But both are hobbled by domestic political challenges, putting prospects for a final deal in question.

Abbas again called on Israel to end the blockade of the Gaza Strip and stop settlement activity. But he also said the Palestinians recognized the need for security, a key Israeli demand amplified by this week's shootings in the West Bank.

We want to state our commitment to follow on all our ... engagements, including security and ending incitement, Abbas said.

The hardline Palestinian Islamist group Hamas, which rules the Gaza Strip, rejected the peace talks and said it would keep attacking Israelis. Four Israelis were killed and two injured in two separate attacks in the occupied West Bank this week.

A spokesman for Hamas, which controls the Gaza Strip, said some 13 militant groups had joined forces to launch more effective attacks against Israel. Asked if this included suicide bombings, he said: All options are open.

Jewish settler groups, meanwhile, vowed to push ahead with new construction in occupied areas of the West Bank, underscoring a central sticking point that threatens to derail the negotiations just weeks after they begin.

Netanyahu and Abbas appeared to be in a conciliatory public mood on Thursday. They met together with Clinton for more than an hour, and then privately one-on-one for about 90 minutes, U.S. officials said.

JEWISH SETTLEMENTS

The talks may hit their first road block when Israel's partial freeze on building new settler homes on the West Bank is set to expire on Sept. 26.

Abbas has said he will pull out of the talks unless Israel extends the self-imposed moratorium, a step that will be tough for Netanyahu, who heads a coalition dominated by pro-settler parties who want to start building again immediately.

Abbas on Thursday again told Netanyahu he would pull out of talks if settlement construction resumed, a senior Palestinian official said.

We'll try our best, but that will all be torpedoed if Mr. Netanyahu goes back to settlements, Palestinian adviser Nabil Shaath told Reuters.

But Netanyahu has appeared reluctant to extend the building moratorium.

The Palestinians say the settlements are a direct threat to their hopes to achieve a homeland on the West Bank and the Gaza Strip, a goal that has eluded them since Israel was founded in 1948.

About half a million Jewish settlers live in communities scattered over the West Bank and in East Jerusalem, and claim a biblical link to West Bank land occupied by Israel since the 1967 war. Major world powers regard the settlements as illegal and a threat to peace.

Mitchell said both sides agreed the talks were sensitive and would therefore release little information about details. He declined to offer specifics when asked if the settlement issue had been discussed.

But Mitchell -- who has spent months shuttling between the two sides to coax them into talks -- said they agreed the first step would be to work up a framework agreement to establish the parameters of a deal.

Rather than specifying the precise lines of a border, such an agreement would lay out main issues -- presumably including the future of Jerusalem, the fate of Palestinian refugees -- in brief terms.

Once you resolve the main issues, then it becomes easier to resolve technicalities, said Ghaith al-Omari, a former Palestinian Authority official now at American Task Force on Palestine, a Washington-based advocacy group.

The United States views the Israeli-Palestinian dispute as having a direct effect on U.S. security and diplomacy around the world. Obama, convening the talks ahead of the pivotal November U.S. congressional elections, met both leaders at the White House on Wednesday and later urged them not to let the chance for peace slip.