Abbas made his comments as negotiators from his Fatah Party plan to meet Hamas officials in Egypt this week for what are expected to be the most serious reconciliation talks since Hamas violently seized power in Gaza nearly two years ago.
"We must reach a national reconciliation government," Abbas said. "This government will be responsible for reconstruction (in Gaza). The faster a government is formed, the faster we will be able to rebuild in the Gaza Strip, quickly, for the sake of our people."
Fatah and Hamas are expected to begin 10 days of talks in Cairo on Tuesday, with senior officials from the sides set to participate. But it remains far from certain whether they will be able to work out a deal.
Hamas defeated Fatah in 2006 a parliamentary election, though Abbas remained president. In June 2007, after five days of civil war, Hamas routed Abbas' forces in Gaza and seized complete control. In addition to the lingering mistrust, the sides must overcome their deep differences over dealing with Israel and the international community.
In his speech, the Western-backed Abbas said a new unity government must accept past Palestinian agreements. That would include recognizing Israel's right to exist, which Hamas rejects. He said the government would serve in a caretaker capacity until new elections are held by next January.
Abbas' prime minister, Salam Fayyad, submitted his resignation on Saturday to clear the way for a unity government. On Sunday, Fayyad urged Palestinians to embrace Abbas' efforts "to ensure the success of the dialogue that Egypt is overseeing."
Better chance of easing blockade
A previous unity government was paralyzed by Hamas' refusal to recognize Israel, before their agreement deteriorated into the 2007 Gaza civil war. Since then, Abbas' internationally recognized government has ruled in the West Bank, while the isolated Hamas regime controls Gaza. The two areas, both claimed by the Palestinians for a future independent state, lie on opposite sides of Israel.
In Gaza, Hamas showed few signs of flexibility heading into the latest talks. "We don't accept any preconditions regarding the platform and the program of the coming government," said spokesman Fawzi Barhoum. "We want a government that can satisfy the needs of our people, not the conditions and dictations of others."
Despite the tough line, Hamas may be forced into moderation following Israel's offensive early this year. The three-week operation killed some 1,300 people, according to Palestinian medics and human rights groups. It also destroyed or damaged some 15,000 homes and caused heavy damage to Gaza's infrastructure.
For reconstruction to take place, Israel and Egypt must lift a blockade of Gaza's borders imposed after the Hamas takeover. A unity government would have a better chance of easing the blockade to allow construction materials and other supplies into Gaza.
The Palestinians also will soon be dealing with a new Israeli government headed by Prime Minister-designate Benjamin Netanyahu, who advocates tough action against Hamas and says the Islamic militants should be toppled.
The Israeli offensive, launched to halt Palestinian rocket attacks, ended with separate ceasefire declarations by Israel and Hamas on Jan. 18. While Egypt has been trying to broker a more lasting truce, sporadic violence has persisted.
In new fighting, Israeli aircraft attacked an empty Gaza City warehouse, causing no injuries, Hamas officials said. The military said the warehouse was used to store weapons. It said aircraft also struck two tunnels along the Egypt-Gaza border used to smuggle weapons into Gaza.