The German mediator involved in negotiations for the release of abducted Israeli soldier Gilad Shalit arrived in Gaza on Monday to relay Israel's answer to Hamas' demands in the talks, the Al-Arabiya TV network reported.

According to the report, the mediator was to meet with Hamas representatives later Monday, but the Islamist militant group would only respond to the Israeli offer after consultations between its leaderships in Gaza and Damascus.

Earlier Monday, a senior Hamas official said the organization is still sparring with Israel over the names of 50 prisoners it wants released in exchange for Shalit.

The official said Israel was still balking at including prominent political leaders and top Hamas militants it holds.

Last week, Israeli and Hamas officials spoke of progress, raising speculation that an agreement could be wrapped up within days. In Gaza, Hamas' interior minister said he hoped a deal would be reached by year's end.

Hamas earlier Monday accused Israel of working to sabotage the prisoner swap deal, saying negotiations were stalled due to Israel's continued refusal to accept the group's demands.

Hamas' public relations supervisor Osama Hamdan told the Al-Hayyat pan-Arab daily that figures in Israel were seeking to make the deal fail by leaking details of the negotiations, in particular with regard to the release of terrorists with "blood on their hands."

The paper quotes Hamas sources as saying that Israel is still refusing the group's demands to release senior militants Ibrahim Hamad, Abdullah Barghouti and Abbas Asayeb.

According to the report, Israel has not even agreed to raise these prisoners' names during negotiations and has rejected Hamas' offers to send them into exile following release.

The newspaper also said Israel would not agree to release five female Palestinians inmates sentenced to life in prison or other extended terms, even though their names were on the original list of 450 "heavy" prisoners set to be exchanged.

These female inmates included Ahalam Tamimi, who was Abdullah Barghouti's right-hand woman and helped carry out the deadly suicide bombing at the Sbarro pizza restaurant in Jerusalem.

Shalit's father: No news of breakthrough in deal

Meanwhile, Shalit's father said Monday that he has received no word of new breakthroughs in negotiations to secure a deal for his son's release.

Noam Shalit, who has recently held a series of meetings with cabinet ministers, said he "was not concerned with whether the number of prisoners to be released is disclosed," despite ongoing debate in Israel regarding the role of censorship in the prisoner swap debate.

On Sunday, the State Prosecutor's Office declared that Israel would release 980 prisoners in exchange for captive soldier Gilad Shalit. The announcement came in response to a petition filed by the parents of terror victims.

Israel and Hamas have promised the German mediator negotiating the swap that the names of inmates released would not be disclosed, in order to ensure productive negotiations without media interference.

The petition, filed by three bereaved parents in conjunction with the Almagor Terror Victims Association, asked to lift military censorship over the developing deal for Shalit's release. The High Court will hear the petition Monday afternoon.

The state prosecutor responded that Israel is weighing the option of freeing 450 prisoners in the initial stage of the deal, "based on security and moral justifications." The unilateral release of 530 more prisoners, to be selected by Israel, is being planned for a later date as a gesture to the Palestinian people. Drafting the criteria for the second stage has yet to begin, nor has a potential list of inmates been compiled.

'An ongoing terror attack'

The state prosecutor wrote that unlike a prisoner release representing a diplomatic agreement or goodwill gesture, the current negotiations for Shalit are tantamount to "an ongoing terror attack" in which Israel is "bargaining" to reach a deal that would exact the lowest possible price.

If an agreement is reached, the state prosecutor stated, it will only be after the government has considered all of the implications of such an exchange, both moral and practical.

He added that as talks progress and both parties reach an agreement on which inmates to release, a list of names will be publicized.

The response also noted that the military censor is entitled to prohibit the publication of any piece of information it believes "will significantly damage the possibility of returning Shalit alive and healthy," or alternatively, if it believes publication will compromise national security.

Moreover, it said, it is virtually impossible to hold public negotiations with a "bitter enemy," a terrorist organization holding a soldier captive and seeking the highest possible price in return for his release.

The state prosecutor wrote that ambiguity is essential to Israel's very existence, and that without it, "it is impossible to hold effective negotiations and reach the goal of returning the abducted soldier to Israel."

National Union chair Yaakov Katz petitioned the High Court Sunday demanding the disclosure of the recommendations and findings of the Shamgar Commission, charged with examining Israel's policy on prisoner exchanges.

Katz lamented that Prime Minister Benjamin Netanyahu and Defense Minister Ehud Barak had refused to release the commission's conclusions, which they maintain have implications for the developing agreement for Shalit.