Palestinian officials have rejected an offer from the Trump administration to attend a meeting a conference about the Middle East hosted by the US in Poland next week.
US officials said the Palestinians were invited to discuss the decades-long conflict with Israel and the administration's plans for peace.
US President Donald Trump's son-in-law and senior White House adviser Jared Kushner is expected to discuss the conflict at the conference, whether the Palestinians attend or not.
Chief Palestinian negotiator Saeb Erekat quickly rejected the invitation, writing on Twitter: "Regarding statements that we have been invited, we can say that only today there was some contact from the Polish side.
"Our position remains clear: We are not going to attend this conference and reiterate that we have not mandated anyone to talk on behalf of Palestine."
In another tweet on Friday, Mr Erekat said: "The US administration dismissed itself from sponsoring the peace process because of its decisions that are contradictory to the international law."
In a separate tweet, Hussein Al Sheikh, a senior Palestinian Authority official, also rejected the invitation, saying only the Palestine Liberation Organisation could speak on behalf of the Palestinian people.
Mr Kushner has been working on a peace plan for more than a year. The Warsaw event will be one of the first occasions where he will discuss the plan publicly, although he is not expected to reveal any details.
The State Department has said more than 40 countries will attended the conference in Warsaw from February 12 to 14.
On Thursday, the Palestinian government branded the event an "American conspiracy".
Among those expected to attend are Israeli Prime Minister Benjamin Netanyahu, as well as US Secretary of State Mike Pompeo, Mr Kushner and Middle East envoy Jason Greenblatt.
In a statement Thursday the Palestinian foreign ministry labelled the meeting "an American conspiracy intended to get the participants to adopt the US views on issues of the region, particularly the Palestine question".
It said the Palestinian government would ignore all conclusions made by the conference.
The Palestinians have refused to talk to the Trump administration since the US leader recognised Jerusalem as Israel's capital in December 2017.
They see the eastern part of the disputed city as the capital of their future state and have said Washington's pro-Israel bias meant the US could no longer be the main mediator in stalled Palestinian-Israeli peace talks. Mr Trump has failed to condemn continued Israeli settlement building, has cut all aid to the United Nations agency for Palestinian refugees and reduced funding for Palestinian schools that serve sick Palestinians.
The Palestinians have accused the Trump administration of emboldening Israel's hard-right government to pursue plans to change the status quo in the region, allowing it to continue building settlements they say will deal a fatal blow to any hope of a contiguous Palestinian state that would include East Jerusalem, the West Bank and the Gaza Strip.
Israel has occupied the first two territories since the 1967 Arab-Israeli War and maintains a blockade of the Gaza Strip which has been in place since 2007 after Hamas rose to power in the enclave.
The Trump administration has delayed multiple times the launch of a proposed Israeli-Palestinian peace plan, though officials still say they still intend to present one.
The Palestinian foreign ministry also criticised Mr Trump for hailing the US embassy move in his State of the Union address on Tuesday.
"The malicious intentions of this administration were reiterated by US President Donald Trump in his State of the Union speech to Congress in which he stressed continuing with the policy of absolute bias toward Israel," said the statement carried on official Palestinian news agency Wafa.