Hamas’ "change and reform" parliamentary committee on Wednesday urged parties involved in the Doha agreement to review its adherence to Palestinian law.
The parliamentary bloc came out against a key clause in the pact under which Abbas would serve both as president and prime minister of a future government.
The legislative bloc includes Hamas’ top Gaza-based leaders Ismail Haniyeh and Mahmoud Zahhar. They did not attend the ceremony in Qatar where Hamas’s political chief in exile, Khalid Mashaal, and Abbas signed the agreement on Monday.
On Wednesday, Fatah official Azzam Ahmad dismissed criticism that the move to bolster unity had no standing in Palestinian law.
"I advise those who reject this to read the laws again; we are a presidential system, not parliamentary."
Analysts have long spoken of a split within Hamas between those in the movement who have controlled the Israeli-blockaded Gaza Strip for the past five years and Mashaal, who had made his base in Damascus.
"We call upon the parties who signed and those who sponsored Palestinian reconciliation to reconsider and … not to bypass Palestinian law," the parliamentary bloc said in a statement, arguing that a dual presidential-prime ministerial role for Abbas would be illegal.
The deal was aimed at reuniting the deeply split Palestinian national movement after past accords that followed Hamas’s takeover of the Gaza Strip in 2007 failed to get off the ground over disagreements over who would head a new government.
Khalil Shaheen, a West Bank political analyst, said Gaza-based Hamas officials viewed acceptance of Abbas as prime minister as a political embarrassment, especially since Hamas defeated Abbas’s Fatah in a Palestinian election in 2006.
He said Hamas could try to resolve its internal dispute by reorganizing power-sharing between its leaders in exile and those in the Palestinian territories.
"Otherwise, and if the dispute continues, it could undermine the implementation of the agreement," Shaheen said.
Fatah lawmaker Abdallah Abdallah defended the Doha agreement saying there was no clause in the Palestinian law preventing Abbas from serving as both president and prime minister.
"It is clear that some people (in Hamas) have personal interests and not nationalist interests and they are trying to find a pretext to undermine such a step that paved the way towards ending the division," Abdallah told Reuters in the West Bank.
The accord is supposed to open the way for presidential and parliamentary election possibly later this year, and to rebuild the Hamas-ruled Gaza Strip following a 2008-2009 Israeli offensive.