U.S. President Joe Biden says he is “outraged and deeply saddened” by the death of an American activist who was shot by Israeli forces while protesting settlements in the occupied West Bank, calling it “totally unacceptable.”

“There must be full accountability," Biden said in a statement released early on Wednesday. "And Israel must do more to ensure that incidents like this never happen again.”

The Israeli military said on Tuesday that Aysenur Ezgi Eygi, a 26-year-old activist from Seattle, was likely shot “indirectly and unintentionally” by its soldiers, and that it had launched a criminal investigation.

That drew a strong rebuke from her family members, who said in a statement that they were “deeply offended by the suggestion that her killing by a trained sniper was in any way unintentional.” They said “the disregard shown for human life in the inquiry is appalling.”

During Friday’s demonstration, clashes broke out between Palestinians throwing stones and Israeli troops firing tear gas and ammunition, according to Jonathan Pollak, an Israeli protester who was there. He said the violence had subsided about a half hour before Eygi was shot.

The military said its forces appear to have aimed at the “key instigator of the riot” and hit Eygi by mistake.

Eygi also had Turkish citizenship.