Israel detains 250 Hamas members

Tel Aviv and the PA launched the round-up after the Islamist militant group claimed responsibility for an attack near Hebron on Tuesday that killed four Israeli settlers, including a married couple with five children.

Around 500 Israeli colonists live in heavily fortified enclaves in the city among more than 100,000 Palestinians.

Palestinian Prime Minister Salam Fayyad's office issued a statement charging that the attack was aimed at undermining his administration's effort to build international support for "the Palestinian position and ending the occupation."

The talks in Washington are to focus on core issues of the conflict, including the status of east Jerusalem, which the international community has earmarked as the capital of the Palestinians' future state.

Mr Netanyahu said that he would not let the shooting derail the negotiations.

But the right-wing PM appeared intent on derailing the talks himself after an aide announced that Jerusalem should remain the "undivided capital of Israel.

"The position of the prime minister is that Jerusalem is one of the core issues that are on the table at the talks," the aide said.

"Our position is that Jerusalem will remain the undivided capital of Israel."

Mr Abbas has warned that he may pull out of talks if Israel fails to extend a 10-month moratorium on West Bank settlement construction that ends in late September.

Following Tuesday's shooting, the hard-line Yesha Council, which represents the settlers, announced it would unilaterally resume construction.

"The Palestinian leadership speaks softly in English while in Arabic it kills," declared Yesha director Naftali Bennett.

Mr Bennett asserted that the illegal settlements serve to protect "the entire West from the onslaught of radical Islam."

The future of the settlements is one of the thorniest issues in the negotiations.

Over 300,000 Israeli citizens now live in illegal West Bank settlements, along with nearly 200,000 others in east Jerusalem.