The head of Egyptian intelligence, Khaled Fawzy, has been a key figure in the negotiations and is due to visit Gaza to meet Hamas officials, including its leader, Ismail Haniya.
It also remains unclear what will happen to Hamas' 40,000 civil servants, who were hired after Abbas forced his employees in Gaza to resign after the Hamas takeover.
The two factions have launched their most ambitious attempt yet at mending a 10-year rift.
Abbas said that all outstanding issues would be worked out between Hamas and the various Palestinian political parties, in line with the Palestinian reconciliation deal worked out in Cairo in April 2011.
Hamdallah said the Authority would take over the Strip's day-to-day governance as well as "security responsibilities". Israel has no choice - it must agree to allow Abbas into Gaza as part of national reconciliation efforts. "In the end we will get to the hard issues and principles", he said. Along with several countries and organisations, Israel considers Hamas a terrorist group and has said it will not deal with a Palestinian government that contains Hamas members. El-Sissi also has good ties with Israel and the US and could help sell any deal to Netanyahu.
Siemens-Alstom rail merger deal includes four-year plant guarantees
Siemens brings in 7.8 billion euros ($9.3 billion) of revenue annually from rail, while Alstom boasts sales of 7.3 billion euros. Siemens president Joe Kaeser added: "This Franco-German merger of equals sends a strong signal in many ways".
In an interview on Monday night Abbas said there would be "one state, one system, one law and one weapon" - in an apparent reference to Hamas's military wing.
A senior Israel official told The Times of Israel on Tuesday that "Hamas is trying to gain worldwide legitimacy without accepting Israel's right to exist, without disarming and without accepting the Quartet principles". The Israeli government has rejected proposals to relieve the situation in the Strip through projects that Hamas can take credit for, such as building a major seaport under worldwide oversight.
Asked if Hamas is willing to drop arms in case a unity government is formed, Haniyeh said Hamas believes "there are two kinds of arms and guns".
Thirdly, Abbas announced on Monday that a Palestinian state is not likely anytime soon. However, he added, no agreement would work "without Hamas embracing the Quartet's three preconditions, which require the Palestinian government to recognize Israel, honor previous agreements and commitments, and abandon violence and terrorism".
UN Middle East envoy Nickolay Mladenov said he was "encouraged" by the developments and wanted to see the Palestinian Authority government exercise full control in Gaza.