A smoke trail is seen as a rocket is launched from the Gaza Strip towards Israel August 20, 2014. \REUTERS/Baz Ratner

RIYADH (Reuters) - Saudi Arabia and the United Arab Emirates will participate in a conference next month in Bahrain aimed at encouraging investment in the West Bank and Gaza Strip, part of U.S. President Donald Trump’s long-awaited Israel-Palestinian peace plan.

The “Peace to Prosperity” economic workshop, to be hosted on June 25-26 in cooperation with the United States, has already been rebuffed by Palestinian officials and business leaders who want their political demands to be addressed in any solution to the decades-old conflict.

The Palestine Liberation Organization (PLO) and Islamist group Hamas have called for an Arab boycott of the meeting.

The Saudi minister of economy and planning will attend, state news agency SPA reported on Wednesday. The UAE Ministry of Foreign Affairs and International Cooperation said Abu Dhabi would also send a delegation.

The Palestinian Authority has boycotted U.S. peace efforts since late 2017 when Trump decided to move the U.S. Embassy from Tel Aviv to Jerusalem and recognized Jerusalem as the capital of Israel, reversing decades of U.S. policy.

The Trump administration has sought to enlist support from Arab governments. The plan is likely to call for billions of dollars in financial backing for the Palestinians, mostly from oil-rich Gulf states, according to people informed about the discussions.

Saudi Arabia has assured Arab allies it would not endorse any U.S. plan that fails to meet key Palestinian demands which include Arab East Jerusalem as the capital of a Palestinian state, a right of return for refugees displaced by the Arab-Israeli wars, and a freeze on Israeli settlements in lands claimed by the Palestinians.

The U.S. initiative follows a recent upsurge in cross-border fighting between Gaza militants and Israel.