A senior Palestinian Hamas movement leader said on Thursday the atmosphere at the third round of inter-Palestinian dialogue in Cairo was positive.

"We have put the principles and the mechanisms of reaching an agreement very soon and we have reached an understanding on most of the issues," said Mahmoud Zahar, the Gaza-based Hamas strongman.

"All the factions have come here with the intention of reaching an agreement and boosting the unity above all the differences," Zahar added. "The issue is not a gain or loss for any party; it is how to restore the unity," he said.

The third round of the Palestinian unity dialogue, which mainly seeks to reconcile rival Hamas and Palestinian President Mahmoud Abbas' Fatah movement, resumed in Cairo on Wednesday.

In the first round of the Egypt-brokered Palestinian unity talks in late February, rival Palestinian factions agreed to form five committees to work on issues related to the Palestinian reconciliation process.

In the second round on March 10-19, the Palestinian factions agreed on forming a transitional unity government to govern until elections are held by January 2010. But differences remained on the government's political program and the electoral law.

Hamas, which won the parliamentary elections in 2006, wants the electoral system to be mixed, including the proportional and the district representation, but Fatah and the rest of the factions want to exclude the constituencies' system.

Hamas also strongly rejects Fatah's proposal that the upcoming government must accept the interim deals the Palestine Liberation Organization (PLO) has inked with Israel.

Split between Hamas, which now controls the Gaza Strip, and Fatah ruling the West Bank, widened following Hamas' violent takeover of Gaza in 2007.