BRUSSELS - The European Union hopes to persuade Palestinian leaders to drop their plans for full United Nations membership this month in return for a nuanced upgrading of their UN observer status, EU diplomats said on Thursday.The EU's foreign policy chief, Catherine Ashton, went to the Middle East this week to mediate between Israel and the Palestinians with the aim of reviving peace talks and averting a Palestinian statehood bid at the UN General Assembly, which begins its annual gathering on Sept. 21.The United States has warned that such an attempt would damage chances of reviving talks and sent envoys to the region this week to lobby the Palestinians.Israel has also said any such move would put an end to negotiations . Prime Minister Binyamin Netanyahu said on Thursday he would address the UN next week and urge the Palestinians to negotiate peace with Israel rather than pursue the bid for full UN membership for a Palestinian state.Diplomats said Ashton was trying to negotiate a package that could include a statement by the Quartet of Middle East negotiators laying out guidelines for future talks between the Israelis and Palestinians.In Brussels, diplomats said her proposal included a text that would not rule out full UN membership for a Palestinian state in the future, but focuses for now on a lesser upgrade of their status coupled with a specific mention of talks."Our idea is to push for an upgrade of the Palestinian status, without excluding full status in the future, but with a reference to negotiations," one senior EU diplomat said.It was not immediately clear whether this would be an upgrading to the status of "non-member state", as held by the Vatican, or some other formulation. Currently the Palestinian Authority has non-member "observer" status at the UN.Palestinian President Mahmoud Abbas vowed on Wednesday "no retreat" from the plans to request full UN membership in the absence of talks with Israel, which were frozen a year ago in a dispute over settlement building in the occupied West Bank.Ashton has played an increasingly active role in the Quartet, which groups the EU, the United States, Russia and the United Nations, since becoming foreign policy chief in December 2009. But her efforts have been complicated by internal divisions in Europe over the Palestinian statehood bid.Should Palestinian statehood be brought to a vote in the UN, the EU's 27 member states could split into three camps, with some opposing the bid, others backing it and several abstaining.France, in particular, appears to be more receptive to the Palestinians' arguments, whereas Germany opposes unilateral declarations without a negotiated settlement between Israel and the Palestinians.To succeed, Ashton would have to persuade US diplomats to get on board. Washington has said that if the Palestinians ignore entreaties and seek full membership status, it will use its veto in the UN Security Council.In Jerusalem, a Netanyahu aide said the Israeli leader did not rule out talks with Abbas even if the Palestinian president presented the UN membership request.The aide noted that the General Assembly probably would not vote on such a membership upgrade resolution until early October, keeping the door open for a resumption of Israeli-Palestinian peace talks and a meeting between Netanyahu and Abbas.