The Middle East diplomatic Quartet found out in Washington how massively bogged down the Israeli-Palestinian peace process is, despite efforts at bringing the parties closer.

Representatives of the Quartet UN Secretary General Ban Ki-moon, EU foreign policy chief Catherine Ashton, US Secretary of State Hillary Clinton, and her Russian counterpart Sergei Lavrov, declined to issue a statement about their evening dinner.

It was likely one of their last meetings before the UN General Assembly in September, when Palestinians intend to push for unilateral recognition of their state despite US and Israeli opposition.

"We're realistic about the gaps, we know that more needs to be done, but ultimately, it's up to the parties to make the tough decisions... and we stand ready to help and facilitate," said a senior Barack Obama administration official, who wished to remain anonymous.

According to the same source, Quartet members all have voiced support for the position taken by Obama, who in May urged the two parties to base the borders of their countries on the 1967 borders with mutually-agreed swaps.

The source added that there is an urgent need to "find a way to resume direct negotiations without delay or preconditions and to begin with a preparatory phase of talks to maximize chances of success."

Peace talks on reaching a deal ground to a halt in September 2010 when Israel failed to renew a partial freeze on settlement construction in the occupied West Bank.

Since then, the Palestinians have refused to return to talks as long as Israel builds on land they want for a future state.

Palestinian President Mahmoud Abbas has vowed to pursue the unilateral bid for recognition barring any prospects of a renewal of negotiations with Israel.

But negotiator Mohammed Shtayeh noted the Palestinians may take their bid for statehood to the UN General Assembly rather than the Security Council, where a US veto is likely, with plans to submit the request to Ban later this month.

Some Security Council members, like France, have indicated they might recognize an independent Palestinian state if peace talks are not back on track by September.

But other countries, including Germany and the Netherlands, are opposed to any unilateral steps and accept the Israeli position that any progress must be made through negotiations.

Israeli Prime Minister Benjamin Netanyahu has called the 1967 borders "indefensible," insisting there could not be a peace agreement unless the Palestinians first recognize Israel as the "Jewish state."

Israel also wants sovereignty over east Jerusalem, annexed after its occupation, as well as large swaths of settlements in the West Bank and a military presence in the Palestinian section of the Jordan Valley.

The Palestinians reject these conditions, and demand a freeze on settlement building in the West Bank and East Jerusalem.

On Sunday, Palestinian official Hanan Ashrawi urged the Quartet to "undertake its responsibilities seriously."

According to the US official, the Quartet is "committed as a group, collectively and individually, to continue this effort and to continue their intense engagement with the parties remain in close coordination as they tackle this difficult challenge."