"Until now Hamas refused to say yes or no to the initiative to put an end to divisions, form a new government and prepare for elections. Now the ball is in their court," Abbas said.
Hamas, while a Sunni Muslim organization, is suspected by Israel and the United States of being funded and armed by Shiite Iran. Tehran says that it provides only moral support to the group against their common enemy,Israel.
"Iran instructs them to do this or to do that, because they are paid – and therefore they obey their instructions," he added.
Abbas said Hamas politburo chief Khaled Mashaal, who lives in exile in Syria, "receives the money, keeps the money in his pocket and gives it to whomever he wants.
"He uses it as a weapon, and has the upper hand. He has the ability to say yes or to say no.
"They (Iran) are not our friends; they don't behave as friends but they are not enemies," he noted.
Hamas and Fatah have been at loggerheads since the early 1990s.
Tensions heightened after Hamas trounced Fatah in 2006 legislative elections and boiled over in 2007, when the enmity erupted into bloodshed that saw the Islamists kick their secular rivals out of Gaza.
Since then, Gaza has been effectively cut off from the West Bank, which is under the control of Fatah, and repeated attempts at reconciliation have led nowhere.
The disunity of the Palestinians has prevented them from taking a common stance in peace talks with Israel, which are now off the table.
Tens of thousands of Palestinians took to the streets of Gaza and the West Bank last month to demand that the two factions end their long-running rivalry, and talks between the sides briefly looked as if they might move forward.
On March 26, Abbas and Hamas held what both sides described as positive talks on the long-elusive reconciliation.
The previous week, Abbas accepted a Hamas invitation to travel to Gaza in a bid to end the division and form a unity government.
"I am with the people and in favor of going back to the people and putting an end to the divisions through presidential and parliamentary elections," he said.
Hamas had previously rejected such appeals, saying it would not participate without first securing some form of reconciliation with the Fatah-dominated Palestinian Authority, which rules the West Bank.
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