Palestinian officials have dismissed proposals unveiled by President Donald Trump's son-in-law, Jared Kushner, for big money projects to form the first economic portion of the Trump administration's long-awaited Middle East peace plan.
Senior Palestine Liberation Organisation (PLO) official Hanan Ashrawi said Mr Kushner's plans were "all abstract promises" and said only a political solution would solve the conflict.
Hamas, the Islamist militant group that controls Gaza, was more blunt, saying: "Palestine isn't for sale".
An Israeli cabinet minister welcomed the plan.
The Trump administration's $50 billion Middle East economic plan calls for creation of a global investment fund to lift the Palestinian and neighbouring Arab state economies, according to US officials and documents reviewed by Reuters.
One proposal is for the construction of a $5 billion transportation corridor to connect the West Bank and Gaza.
The "peace to prosperity" plan is set to be presented at an international conference in Bahrain next week by Mr Kushner, who told Reuters that Palestinian leaders should consider the initiative.
"This is going to be the 'Opportunity of the Century' if they have the courage to pursue it," he said.
However Ms Ashrawi, a veteran Palestinian negotiator and member of the executive committee of the PLO, said only a political solution that ended Israel's occupation of the Palestinian Territories would solve the conflict.
Speaking to Reuters by phone from the West Bank city of Ramallah, she said: "If they really care about the Palestinian economy they should start by lifting the siege of Gaza, stopping Israel stealing our money and our resources and our land and opening up our territorial waters, our air space and our borders so we can freely export and import."
She said the Trump administration's stance was an "entirely wrong approach", adding: "They can end the occupation, which is the most basic requirement for prosperity. There can be no prosperity under occupation."
Israeli Energy Minister Yuval Steinitz said the plan looked promising.
"What's been published until now looks good and even very good. We are always in favour of developing the Palestinian economy, ending the humanitarian crisis in Gaza, ensuring economic prosperity in the Palestinian communities," he told Israeli Reshet TV.
"The entire world wants to help the Palestinians except for the Palestinians themselves."
No Palestinian officials belonging to Palestinian President Mahmoud Abbas' PLO and Palestinian Authority will attend the conference in Bahrain. The White House said it decided against inviting the Israeli government because the PA would not be there.
Several Gulf Arab states, including Saudi Arabia, will participate in the June 25-26 US-led gathering in Manama. Their presence, some US officials say privately, appears intended in part to curry favour with Mr Trump as he takes a hard line against Iran, those countries' regional arch-foe.
The economic revival plan would take place only if a political solution to the region's long-running problems is reached.
More than half of the $50 billion would be spent in the economically-ravaged Palestinian territories over 10 years while the rest would be split between Egypt, Lebanon and Jordan. Some of the projects would be in Egypt's Sinai peninsula, where investments could benefit Palestinians living in adjacent Gaza, a crowded coastal enclave impoverished by an economic blockade.
In Gaza, Hamas official Ismail Rudwan also rejected Mr Kushner's proposals.
The armed Islamist group is the main internal rival to Abbas, whose power base is in the West Bank. But both are in rare agreement over the Trump administration.
"We reject the 'deal of the century' and all its dimensions, the economic, the political and the security dimensions," Mr Rudwan told Reuters.
"The issue of our Palestinian people is a nationalistic issue, it is the issue of a people who are seeking to be free from occupation. Palestine isn't for sale, and it is not an issue for bargaining. Palestine is a sacred land and there is no option for the occupation except to leave," he said.