RAMALLAH, West Bank, Aug 13 (Ali Sawafta/Reuters) - Palestinian President Mahmoud Abbas will submit an application for full U.N. membership at the General Assembly next month, his foreign minister said on Saturday, without specifying exactly when the request would be made.

I think that the president, when he gets to the United Nations and meets the secretary general, will present the application, Foreign Minister Riyad al-Malki said in a briefing in Ramallah.

Malki's statement narrowed down the timing of the application to September during Abbas' visit to New York, but when asked give a specific date, Palestinian officials said it would still have to be determined.

This year's 66th General Assembly meetings are set to open officially on Sept. 13 with high-level meetings of world leaders expected to start on Sept. 20.

With peace talks with Israel deadlocked for months, Abbas hopes to win U.N. endorsement for the Palestinian claim to statehood in all the Israeli-occupied West Bank, East Jerusalem and the Gaza Strip.

But the United States, which has veto power in the U.N. Security Council, is expected to oppose any Abbas bid to seek a unilateral U.N. mandate for statehood in the absence of peace talks with Israel.

In a separate move, the Palestinians have signaled they will seek an upgrading of their status from observer entity to non-member state. This is expected to pass as it does not require Security Council approval.

Israeli Prime Minister Benjamin Netanyahu issued a statement expressing regret at the move.

It was expected and is regrettable. (The prime minister) still believes that only through direct and honest negotiations, not through unilateral decisions, will it be possible to advance the peace process, the statement read.

(Writing by Ori Lewis)