Abdallah is among 29 journalists reported to have been killed since the attack on October 7, which has prompted the Israeli military to carry out massive air strikes in Gaza and launch a ground operation.
RSF said: “According to the ballistic analysis carried out by RSF, the shots came from the east of where the journalists were standing; from the direction of the Israeli border.”
"Two strikes in the same place in such a short space of time (just over 30 seconds), from the same direction, clearly indicate precise targeting."
Abdallah was near the village of Alma al-Chaab with six other journalists, covering the exchange of fires between the Israeli forces and Lebanese militia Hezbollah.
RSF said its preliminary findings were based on “thorough analysis of eyewitness accounts, video footage and ballistics expertise.”
RSF did not explicitly state who launched the strike, but found that it is unlikely the reporters were mistaken for combatants as they were wearing helmets, a vest marked ‘press’ and in plain view for over an hour.
Jonathan Dagher, head of the Middle East desk said there are other elements that they have yet to confirm, but they are “certain” of their findings.
Reuters said in a statement: "We are reviewing the preliminary conclusion reached by Reporters Without Borders (RSF), which found that Issam Abdallah and other journalists in Alma el-Chaab appear to have been deliberately fired upon from the direction of Israel on 13 October.”
“We reiterate our call to the Israeli authorities to conduct a swift, thorough and transparent probe into what happened. And we call upon all other authorities with information about the incident to provide it. We will continue to fight for the rights of all journalists to report the news in the public interest free of harassment or harm, wherever they are."
Lebanon's army and government have blamed Israel for Abdallah's death. A Lebanese military source told Reuters that the claim is supported by a technical on-the-ground assessment carried out after the attack.
The Israeli Defence Forces did not immediately respond to a request for comment from Reuters on the RSF findings. It has said that it does not target journalists deliberately and that it is investigating the incident.