The personal material was part of an 80-page report by Hezbollah detailing the group's search for Arad, who was shot down over Lebanon and captured alive in 1986.

The letters were addressed to Tami and spoke of his love for her and their infant daughter Yuval, said the family's lawyer, Eliad Shraga.

While the letters and diary fragments were kept private, the two photographs were released to the public on Sunday.

The report, which did not solve the mystery of what happened to Arad, represents the first stage of a planned prisoner swap that includes the release of reservists Eldad Regev and Ehud Goldwasser, who were captured by Hezbollah in July 2006.

The Hezbollah report is merely an updated version of a report it passed to Israel in 2004, defence officials said.

The new information, apartfrom the personal documents and photographs from Arad, concern efforts made by Hezbollah to find Arad, including, according to Israeli television, names of people it interrogated who might be able to provide Israel with new leads.

But the conclusion remains the same as the 2004 report, said defence officials: that Arad went missing somewhere between the night of May 4, 1988 and the morning of May 5, and probably died.

Defence Minister Ehud Barak said that Israel would proceed with the prisoner swap - scheduled for this week - even though the Hezbollah report failed to explain what had happened to Arad.

Barak said he had a "moral responsibility" to proceed with the deal to return Goldwasser and Regev.

The Arad family, which believes that Hezbollah has more documents from Arad, is demanding that the Islamist organisation release all that information.

This is not the first time that material from Arad has surfaced. In October 2007, Tami Arad received a letter written by her husband that was transferred to Israel as part of a swap deal with Hezbollah involving the corpse of Beersheba man Gavriel Daweet, who drowned off Nahariya in 2005 and washed ashore in Lebanon.