BETHLEHEM (Ma'an) -- President Mahmoud Abbas and Hamas chief Khalid Mashaal are expected to agree on the structure of a Palestinian national unity government during their meeting in Cairo on Thursday.

Secretary-general of Fatah Revolutionary Council Amin Maqboul told Ma'an Monday that failure to appoint a new government was the main obstacle to elections in the West Bank and Gaza.

Mashaal, who lives in exile, arrived in Jordan on Sunday where he met King Abdullah II, his first visit since being expelled from the country in 1999.

Abbas' party Fatah and rivals Hamas signed a reconciliation deal in May last year to end four years of divided government. The parties have headed rival administrations in the Gaza Strip and West Bank since fighting escalated to near civil war in 2007.

The reconciliation deal set out a path to elections within a year, and the appointment of an interim government to unite both territories. But the parties could not agree on a candidate to lead the unity government.

After meeting in November to kickstart the stalled deal, Mashaal and Abbas indicated that elections would still be held by May 2012, and established several committees to oversee implementation of the deal, including the release of political prisoners, which have yet to deliver on its terms.

Maqboul told Ma'an that the Central Elections Commission has ruled out the possibility that elections will be held at the beginning of May as suggested.

According to Palestinian electoral law, President Abbas must issue a decree three months before elections are held.

An official in the CEC said the commission would need six weeks to register voters in Gaza, as the registrar had not been updated in five years. But the elections were pending a presidential decree, he said.

The electoral body reopened its Gaza headquarters last week after a two-year closure. Hamas shut down the office in November 2009 saying fair elections could not be held while political activists were threatened by the infighting.

Jamil Khalidi, who heads the commission's office in Gaza, told Ma'an last Thursday that they could complete the necessary preparations in time for a May vote if the president orders elections.

(This version CORRECTS the proposed location of Thursday's meeting. Abbas and Mashaal are scheduled to hold talks in Cairo, not Amman.)