Fatah has accepted Egypt's invitation for Palestinian factions to sign a reconciliation agreement this month.
But rival Hamas says Fatah leader Mahmoud Abbas's smothering of a UN report on Israel's Gaza war conduct could prove fatal for any unity deal.
Ahmed Abul Gheit, Egypt's foreign minister, told a joint press conference in Jordanian capital Amman on Monday that Cairo would host talks between Palestinian factions on October 25 "before signing a reconciliation agreement on October 26".
The announcement came shortly after Abul Gheit and Omar Suleiman, Egypt's intelligence chief, held talks with Abbas, who is also the Palestinian president.
A senior Fatah leader, Azzam al-Ahmad, who is in charge of national reconciliation efforts, told Palestine TV that his faction had accepted Egypt's invitation to sign the deal.
But new tension between Abbas and Hamas threatens to derail the pact.
Hamas lashed out at Abbas for backing the deferment of a vote on the UN's Goldstone report which could have led to the prosecution of Israel for war crimes during its offensive against Gaza.
Ismail Haniya, the Hamas leader in Gaza, accused Abbas of making an "absurd and criminal" decision to delay endorsing the report, saying the move could hurt unity talks.
"How can the two parties [Fatah and Hamas] sit at one table and sign an agreement in this situation? ... This has placed a heavy obstacle in the way of Palestinian unity," he said on Monday.
Speaking to Gaza legislators on Monday Haniya said Abbas, by agreeing to defer the UN vote, had "justified" the Israeli war.
The move by Abbas "cannot be seen as a conciliatory act" and reflected an attitude that "would perpetuate internal turmoil", he added.
Other Hamas leaders at the special legislative session held in Gaza City accused Abbas of committing "national treason".
Mahmoud al-Zahar, a senior Hamas official, called for Abbas to be tried in court and stripped of Palestinian citizenship.
And he appeared to rule out signing any reconciliation deal under the present circumstances.
"I personally would prefer to postpone it because we cannot sit down with this criminal who made such mistakes to the degree of killing our people," he said.
But Abul Gheit was confident that "the Goldstone issue is not likely to affect Palestinian reconciliation".
The rivalry between Hamas and Fatah came to a head in June 2007 when Hamas routed Fatah forces and seized control of Gaza after 18 together in a shaky coalition government.
Egypt has twice postponed the scheduled date for the signing of a reconciliation agreement because of continuing disagreements between the two main Palestinian factions.