Essential issues that the inter-Palestinian dialogue tries to overcome are still outstanding, a Hamas official said on Wednesday.

As a result, the Islamic movement and President Mahmoud Abbas's Fatah party agreed to hold a fifth round of talks in the middle of next month. The postponement followed two days of talks in Cairo.

"The main problems are still unsolved," said Mushier al-Massri, a Hamas lawmaker based in Gaza. He explained that the political program of the government that his movement tries to form with Fatah is considered one of the hardest obstacles.

Hamas says Fatah's insistence to reflect international conditions in the government's platform blocks the way to an agreement. Al-Massri adds that Fatah also wants Hamas to stick by the Palestinian Liberation Organization's (PLO) commitments towards peace with Israel.

"Hamas will try to be flexible as much as possible but can not make concessions on any rights or principles," al-Massri said. "But Fatah insists that the Quartet's conditions be present in the government's program and this means the recognition of Israel, renouncing the resistance and approving the PLO's commitments that give up 78 percent of Palestine's land."

Fatah argues that a Palestinian government acceptable to the international community would enjoy support and recognition by the world and will be able to lift the Israeli siege on the Palestinian territories, especially the Hamas-controlled Gaza Strip.

The Cairo talks aim at reconciling Hamas and Fatah by forming a unity government replacing Hamas's administration of Gaza and the Western-backed government of West Bank.