US President Donald Trump's break with decades of support for a two-state solution to the Israeli-Palestinian conflict is irresponsible and does not advance peace, a senior Palestinian said.
"This does not make sense," Palestine Liberation Organisation executive committee member Hanan Ashrawi said.
"This is not a responsible policy and it does not serve the cause of peace.
"They cannot just say that without an alternative."
On Tuesday, a senior White House official said the United States would no longer seek to dictate the terms of any eventual peace settlement by insisting on a Palestinian state alongside Israel, but would support whatever the two sides agree to together.
The comments came on the eve of White House talks between Trump and Israeli Prime Minister Benjamin Netanyahu.
Another official said: "A two-state solution that doesn't bring peace is not a goal that anybody wants to achieve."
A spokesman for Hamas, the Palestinian Islamist movement that controls Gaza, said the announcement was "confirmation that the so-called peace process is an illusion."
For the better part of half a century, successive US governments - both Republican and Democrat - have backed a two-state solution.
Trump has yet to speak directly to the Palestinian leadership.