After a meeting in Cairo on Wednesday between Abbas, the Palestinian president, and Hosni Mubarak, his Egyptian counterpart, the head of Egypt's intelligence service urged Hamas to take steps on three key issues.
Omar Suleiman, who also attended the meeting, said: "One, to stop the violence. Two, it should become a doctrine for them to be committed to all the agreements signed with Israel. Three, they have to recognise Israel.
"If they don't do it, Abu Mazen [Abbas] will not ask them to form the government. Abu Mazen will [instead] form the government with other parties.
"If they don't accept to commit themselves to these issues, nobody will deal with them."
Mohammed Sobeih, the Palestinian representative to the Arab League, told AFP earlier that a meeting was scheduled to take place in Gaza on Friday during which Abbas and Hamas officials were expected to discuss the formation of the government.
Hamas - which has spearheaded attacks against Israel in recent years and does not recognise the existence of the Jewish state - won the Palestinian parliamentary elections last week.
Ahmed Qorei, the Palestinian prime minister, resigned after the elections but the prospect of Hamas heading the next cabinet has unsettled Israel and Western powers.
Livni, the Israeli foreign minister,
also arrived in Cairo for talks
Tzipi Livni, the Israeli foreign minister, also arrived in Cairo on Wednesday for talks with Mubarak.
She has said that Israel could halt the transfer of customs duties to the Palestinians.
Major players in the international peace process, including the United States and European Union, have also threatened to slash funding to the Palestinian Authority unless Hamas renounces violence and recognises the Jewish state's right to exist.
A delegation from Hamas crossed into Egypt on Wednesday and was due to hold talks in Cairo on the first leg of a tour of Arab countries, but the movement appeared in no mood to make radical changes to its policy.
Reacting to earlier demands by George Bush, the US president, for the radical movement to end violence and recognise Israel, Mushir al-Masri, the Hamas spokesman, told AFP that the Palestinian people were being "blackmailed".
Hamas has denounced most agreements between the Palestinian Authority and Israel, including last November's deal on the reopening under EU surveillance of the Rafah border crossing between the Gaza Strip and Egypt.
"It is hard to convince them to change 180 degrees. I hope it will happen," Suleiman told reporters. "You know they are very radical and it is hard to convince them."
Hamas implicitly calls in its charter for the destruction of Israel and supports the establishment of a Palestinian state on its historical borders, stretching from the Jordan river to the Mediterranean.
"We understand that they [the Western states] need a quiet region, without conflicts, and we know that it's possible to attain this goal"
Moussa Abu Marzouk,
deputy head of Hamas's political bureau
Meanwhile, a senior Hamas official said last year's ceasefire with Israel could be renewed to placate the Western powers concerned with its triumph at the polls.
Moussa Abu Marzouk, the deputy head of Hamas's political bureau, said: "We understand that they [the Western states] need a quiet region, without conflicts, and we know that it's possible to attain this goal. Truce is one of the projects through which we could deal with.
"I believe that this [ceasefire] would placate everybody if they understand Hamas's stand and talk to Hamas on these grounds. I believe that this is one of the options which we could propose in the future to co-operate with the international community to bring about peace and tranquility to this region."