Israel has for the first time formally confirmed that it is contemplating the release of 980 prisoners in exchange for Gilad Shalit, the soldier seized nearly three-and-a-half years ago by militants in Gaza.

Although it does not mean that a deal that has yet been agreed with Hamas, which is holding Sergeant Shalit, the official declaration for the High Court by the state prosecution service is bound to excite further speculation that a deal is imminent.

The statement, a response to a petition by parents bereaved in suicide and other attacks by Hamas and other militants, says that "as part of an agreement with Hamas" for the return of the captive, "there is a possibility for the release in principle of about 450 prisoners whose names are being delivered by Hamas". It adds that the Hamas names are being "examined in detail in accordance with different considerations and based on rationales of security and values". And it goes on to say that in a second stage "as a gesture to the Palestinian people", another 530 prisoners will be released, though that list has not yet been compiled.

The first specific detailing of figures come after a welter of media speculation about a breakthrough in negotiations for the prisoner exchange. The latest is a report by the German news magazine, Der Spiegel, that one will go ahead. The German BND intelligence agency is mediating between the two sides.