PARIS, France - Two Israeli tank rounds were used in the attack that killed a Reuters journalist and wounded six others in southern Lebanon on October 13, an investigation published Thursday by the news agency found.

Issam Abdallah, 37, was killed instantly in the incident. The others present -- two other Reuters journalists, two from Qatari broadcaster Al Jazeera, and two from AFP -- were all injured.

AFP photographer Christina Assi, 28, was seriously wounded, later had a leg amputated and is still in hospital.

An AFP investigation conducted with Airwars, an NGO that investigates attacks on civilians in conflict situations, showed that the first strike involved a 120-mm tank shell only used by the Israeli army in this region.

Amnesty and Human Rights Watch also concluded that the first strike that killed Abdallah and severely wounded Assi was most likely a tank round fired from Israel.

For its investigation, Reuters worked with the Netherlands Organisation for Applied Scientific Research (TNO), an independent research institute which works with the Dutch defence ministry.

The probe pointed to "the tail fin of a 120 mm tank round fired by a smoothbore tank gun positioned 1.34 km away from the reporters, across the Lebanese border".

It analysed evidence from the scene, satellite images and hours of footage, including footage from Italian broadcaster Rai "that showed the launch point of the second strike as well as the tank round in flight, and the audio of the firing and the impact of both rounds taken from Al Jazeera's live feed".

"Using the Al Jazeera audio, TNO calculated the interval between the sound of the two strikes and the thud of the muzzle blasts to determine that the firing point was 1,343 metres away from the reporters," Reuters said.

"It said the sound signatures from the strikes matched, showing they were both tank rounds fired from the same position."

It determined they originated from an Israeli military outpost in Jordeikh next to the border.

"The evidence we now have, and have published today, shows that an Israeli tank crew killed our colleague Issam Abdallah," Reuters editor-in-chief Alessandra Galloni said.

"We call on Israel to explain how this could have happened and to hold to account those responsible for his death and the wounding of Christina Assi of the AFP, our colleagues Thaier Al-Sudani and Maher Nazeh, and the three other reporters," she said.