U.S. President Joe Biden has sparked outrage from the family of Turkish American activist Ayşenur Ezgi Eygi for characterizing her shooting by an Israeli sniper in the occupied West Bank last week as "an accident."

Biden said he thought the killing of Eygi was an "accident," but both Secretary of State Antony Blinken and Pentagon chief Lloyd Austin called it "unprovoked and unjustified."

In a White House statement on Wednesday, Biden doubled down on Israeli claims, saying Israel has acknowledged its responsibility for Ayşenur’s death, and that a preliminary investigation has indicated it was the result of "a tragic error resulting from an unnecessary escalation."

After an initially measured response to Eygi's death on Friday, pending a fact-finding exercise, Blinken said the United States would raise it at senior levels with its key ally.

The investigation, and eyewitness accounts, make clear "that her killing was both unprovoked and unjustified," Blinken told reporters on a visit to London.

"No one should be shot and killed for attending a protest," he said.

"In our judgement, Israeli security forces need to make some fundamental changes in the way that they operate in the West Bank, including changes to their rules of engagement.

"We have the second American citizen killed at the hands of Israeli security forces. It's not acceptable. It has to change."

U.S. Defense Secretary Lloyd Austin spoke with his Israeli counterpart Yoav Gallant on Tuesday, urging him to "reexamine the (Israeli military's) rules of engagement while operating in the West Bank," according to a readout of the call from the Pentagon.

Eygi, who was 26 and also held Turkish citizenship, was killed as she attended the site of weekly demonstrations against Israeli settlements, which are illegal under international law but supported by right-wing members of Prime Minister Benjamin Netanyahu's government.

The Israeli military said it had found that it was "highly likely that she was hit indirectly and unintentionally by IDF (Israeli army) fire."

It added that the fire "was not aimed at her, but aimed at the key instigator of the riot."

‘Wholly inadequate’

But Eygi's family rejected the military's version of events and called its preliminary inquiry "wholly inadequate."

"She was taking shelter in an olive grove when she was shot in the head and killed by a bullet from an Israeli soldier," they said in a statement.

"This cannot be misconstrued as anything other except a deliberate, targeted and precise attack by the military against an unarmed civilian."

"As we mourn the death of our beloved Ayşenur, we reiterate our demand for US government leaders – President Biden, Vice President (Kamala) Harris and Secretary of State (Antony) Blinken – to order an independent investigation into the Israeli military's deliberate targeting and killing of a U.S. Citizen," the statement added.

Eygi's partner Hamid Ali too disputed that account, saying in a statement that "this was no accident and her killers must be held accountable."

Biden has also not spoken with the family of Eygi to offer his condolences, White House National Security Council spokesperson John Kirby said Monday in response to a question.

A Palestinian eyewitness said that the Israeli sniper who killed Eygi "cried out for joy" after shooting her while an Israeli activist who was there for the protests that day said: "The soldier who did this took a kill shot. That kill shot was no isolated incident."

Turkish authorities on Monday said they were working to bring Eygi’s body to her family in Türkiye for burial.

President Recep Tayyip Erdoğan said Ankara would do everything possible to ensure "that Ayşenur Ezgi's death does not go unpunished."