Informed Palestinian sources have told Al Jazeera that a ceasefire agreement between Gaza-based resistance groups and Israel would be announced Tuesday evening in Cairo.

The agreement reportedly calls for an immediate halt to all hostilities.

Egypt, the sources said, was prepared to guarantee the terms of the agreement.

The ceasefire deal is expected to be announced at a joint press conference Tuesday evening held by representatives of Hamas, the Islamic Jihad and Egypt.

The announcement came hours after Egyptian President Mohamed Morsi stated that Israel's latest aggression on Gaza would "end" on Tuesday.

Morsi also asserted that Egyptian mediation efforts would produce "positive results" within "hours."

Israel, for its part, has refused to comment on the Egyptian president's statements.

The Muslim Brotherhood's Freedom and Justice Party, for its part, has said the agreement had already been signed by both sides.

On Tuesday evening, however, Reuters quoted an Israeli government spokesman as saying that a ceasefire deal had yet to be finalised. "The ball is still in play," the spokesman was quoted as saying.