Prime Minister Ehud Olmert gave his two top negotiators a Sunday deadline to win the release of an Israeli soldier captured by Palestinian militants as part of a final push to strike a deal with Hamas before he steps down.

Olmert said he sent Shin Bet security service chief, Yuval Diskin, and veteran prisoner-swap negotiator Ofer Dekel to Cairo over the weekend to make "an additional effort" in Egyptian-mediated talks with the radical Hamas movement, which has been holding Sgt. Gilad Schalit since June 2006.

"I instructed them to complete the talks by this evening," Olmert said at the start of the weekly Cabinet meeting Sunday. "It is my intention to convene tomorrow a special Cabinet meeting to hear a situation report and to take any decision that is required according to the report we receive."

Israeli media was buzzing Sunday with hopes that Diskin and Dekel would return with a deal for government endorsement. But ahead of Sunday's meeting, Cabinet Minister Isaac Herzog urged caution.

"We do not know exactly what the (Hamas) demands are, they haven't been put to us, they will certainly be presented tomorrow," he said. "I think it would be appropriate to keep our expectations realistic."

In Cairo, Hamas spokesman Fawzi Barhoum told The Associated Press that there had been no new developments, and he considered Olmert's statement, and the arrival of the negotiators, to be bargaining tactics.

"We have not received anything new," he said. "We will not change our position."

Hamas is seeking the freedom of hundreds of Palestinian prisoners held by Israel, including dozens involved in deadly attacks on Israelis, in exchange for Schalit. Israel has a long history of agreeing to lopsided swaps to bring home soldiers captured or killed in battle.

Local media reports said the last stumbling block was an Israeli demand that some of the prisoners slated for release be deported to the Gaza Strip or elsewhere after they are freed. Israel fears that they would carry out new attacks if they are permitted to return to their homes in the West Bank.

Olmert, who is leaving office under the shadow of fraud investigations and wide criticism for his handling of the flawed 2006 war in Lebanon, is eager to announce Schalit's release before he hands over to Prime Minister-designate Benjamin Netanyahu.

Dekel also traveled to Cairo last week for talks with Egyptian officials as part of Olmert's final push for Schalit's release. He is a former deputy director of the Shin Bet, Israel's internal intelligence agency that is mainly concerned with keeping tabs on Palestinian militant groups.

Netanyahu has been trying to put together a coalition government since February elections. His Likud Party was negotiating Sunday with prospective partners and he is expected to finish the task this week.

Netanyahu takes a tough line against Hamas, and the Schalit family fears that with a new government in office, negotiations to free the soldier will have to start all over.

Schalit, 22, was captured by Hamas-allied militants in June 2006 in a cross-border attack that killed two other soldiers. He has not been seen since and the Red Cross has not been allowed to visit him, though Hamas has released two recorded statements from him and exchanged letters between him and his family.

Sensing that time is running out, the Schalit family has intensified lobbying for his release. His parents have joined a vigil in a protest tent outside Olmert's Jerusalem residence, and his older brother, Yoel, gave his first television interview on Saturday night.

"This is the last week that the decision-makers have to honor their commitment to save Gilad," he told Israeli Channel 2.

In a country where military service is mandatory, many Israelis strongly identify with the Schalits, attending mass rallies and vigils urging the government to do more for his release.

Others, however, maintain that meeting Hamas' demands would put dangerous militants back on the streets and encourage future abductions of soldiers to use as bargaining chips.

Visiting the Hamas-ruled Gaza Strip on Sunday, the secretary-general of the 57-member Organization of the Islamic Conference, condemned Israel's fierce January offensive there as "awful aggression" that he said breached the rules of war and standards of human rights.

Ekmeleddin Ihsanoglu was accompanied by 30 officials from aid organizations and financial organizations, among them the Islamic Development Bank and the U.K.-based Islamic Relief charity, looking at Gaza's reconstruction needs following war damage estimated at $2.8 billion.