US Secretary of State Antony Blinken has promised to pursue accountability over the killing of Al Jazeera journalist Shireen Abu Akleh wherever facts lead, amid a heated dispute between Israeli and Palestinian authorities on how she died.

The well-known veteran journalist, a Palestinian American, was killed on May 11 as she was covering an Israeli army raid in the Jenin camp in the north of the occupied West Bank.

Appearing at a forum for student journalists on the sidelines of a Latin America summit in Los Angeles on Tuesday, Blinken was confronted by Abby Martin, the host of the independent documentary and interview series The Empire Files. Martin asked why there have been “absolutely no repercussions” for Israel, an historic United States ally.

“I’m sorry, with respect, they have not yet been established,” Blinken said of the facts behind the case.

“We are looking for an independent, credible investigation. When that investigation happens, we will follow the facts, wherever they lead. It’s as straightforward as that,” he said.

Blinken, who has spoken to Abu Akleh’s family, said: “I deplore the loss of Shireen. She was a remarkable journalist, an American citizen.”

Dozens of lawmakers from Blinken’s Democratic Party have called on the FBI to lead an investigation to seek an impartial finding into her death. The US State Department, however, has said that it would trust Israel to conduct a probe.

On Monday, Senator Mitt Romney called on President Joe Biden’s administration to push for “a full and transparent investigation” into the killing of Abu Akleh in a rare move from a Republican Party politician.

Romney, the senator from Utah, sent a letter on Monday to US Secretary of State Antony Blinken, urging the State Department to ensure accountability for Abu Akleh’s killing, which caused global outrage and condemnation.

Palestinian journalists and colleagues – including Al Jazeera cameraman Majdi Bannoura – who were with Abu Akleh when she died said she was killed by an Israeli sniper. A Palestinian probe said that an Israeli soldier shot her dead in what it described as a war crime. A CNN report, quoting witnesses, also said that she appeared to have been killed in a targeted attack by Israeli forces.

Israel has changed its story several times, ranging from denying the allegations, to blaming the killing on stray fire from Palestinian armed fighters, to admitting that an Israeli soldier could have mistakenly shot Abu Akleh.

Israeli authorities asked the Palestinian Authority to take part in a joint probe, and then announced that they will not investigate their own soldiers.

Israeli police attacked Abu Akleh’s funeral procession in occupied East Jerusalem and beat pallbearers carrying her coffin with batons in scenes that spurred further anger and calls for accountability.

Al Jazeera Media Network has assigned a legal team to refer the killing to the International Criminal Court (ICC) in The Hague.