Hamas has said that the release of Gilad Shalit, an Israeli soldier captured in 2006, will not form part of any truce agreement with Israel.
Israel has said a ceasefire deal must include the release of the soldier.
Cpl Shalit was seized in a cross-border raid two years ago by Palestinian militants, including members of Hamas.
Egyptian intelligence chief was in Jerusalem on Monday talking to Israeli officials about a ceasefire offer by the Gaza Strip's militant groups.
Omar Suleiman has for months been involved in talks with all the militant groups in Gaza - finally producing a joint truce proposal at the end of April.
Israel's Prime Minister Ehud Olmert discussed the subject in a meeting with Mr Suleiman on Monday.
Mr Olmert's spokesman, Mark Regev, said: "Hamas continues to hold hostage the young Israeli serviceman - he must be released."
"Hamas cannot expect Israel to ignore the fact that they are holding one of our young servicemen", he added.
Prisoner exchange
The senior Hamas leader Mahmud Zahar responded in a speech in Gaza City by saying: "Whoever thinks that the Shalit issue will be settled for free as part of the period of calm is completely wrong."
He went on: "The issue of a prisoner exchange is completely separate from the period of calm."
Hamas has demanded the release of 450 Palestinian prisoners in exchange for the return of Cpl Shalit.
Hamas leader Khaled Meshaal said in March that the soldier was still alive, and was being well treated.
Violence has been continuing in the region, with militants from the Islamic Jihad movement launching rockets at Israel on Monday, killing one woman.
Israel has been carrying out regular raids on Gaza in an attempt to stop the rocket attacks.
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