Planned talks between Palestinian Authority President Mahmoud Abbas and the political head of rival Palestinian faction Hamas have been postponed.
Abbas (L) was to meet Meshaal in Damascus
The talks were due to take place in Damascus, Syria, where Khaled Meshaal of Hamas lives in exile.
Hamas, which won polls last January, and Mr Abbas's Fatah faction have tried to agree a unity government for months.
Mediation was under way to resolve certain issues so the talks could be held on Sunday, a Hamas official said.
Mr Abbas has already held talks with Syrian President Bashar al-Assad.
The BBC's Rachel Harvey in Damascus says the postponement comes because both sides know if the talks are held, it is important a result is achieved.
The talks would probably focus on who would control which ministries and what kind of policies a unity government might pursue, particularly in relation to Israel.
Hamas politburo member Izzat al-Rishq said: "Efforts are under way to convene the meeting tomorrow."
He said there were outstanding "disagreements" on the formation of a government.
Fatah advocates negotiations to found a state alongside Israel, while Hamas refuses to recognise Israel's right to exist.
Mr Abbas threatened in mid-December to hold fresh elections if a deal could not be reached. Hamas said that was tantamount to a coup.
More than 30 Palestinians have been killed in factional violence since then.
Mr Rishq earlier told Reuters news agency the talks would try to solve "the issue of the final language of the manifesto and those in charge of three key ministries (interior, finance and foreign affairs).
"This is not a last chance meeting. Both sides are aware that prolonging crisis and confrontation only serves Israel."
Mr Abbas's talks with President Assad were described as "frank" and "amicable".
Palestinian legislator Nabil Amr said Mr Assad expressed willingness to back all "efforts aimed at achieving Palestinian unity".