Palestinian Authority President Mahmoud Abbas hinted that a former top Fatah official and several of his cohorts had assisted Israel against the Palestinians over a decade ago, igniting a storm among Palestinians.

Abbas’s hour-long laundry list of accusations, including the charge of spying, against former aide Mohammed Dahlan — delivered to a closed-door meeting of the Fatah Revolutionary Council Monday but released publicly on Wednesday — signaled that the battle over who will succeed the 79-year-old Palestinian president is heating up.

Abbas also claimed that complaints had been filed to the president’s office that Dahlan, a former security head for Fatah in Gaza, was mixed up in the Gaza assassination of Salah Shahadeh, the leader of Hamas’ military wing who killed by an Israeli airstrike in 2002.

In response, Dahlan and senior Hamas figures slammed Abbas and demanded that he open an inquiry into the issue.

Hamas spokesperson Taher al-Nunu demanded an investigation into the veracity of Abbas’s claim that military officials from Fatah, involved in security coordination with Israel, were mixed up in the affair.

On his Facebook page, al-Nunu wrote that Abbas’s comments “blaming Dahlan for the assassination of Salah Shahadeh” were dangerous, and warned of repercussions.

Al-Nunu added that “if there is truth to the matter, why has [Abbas] kept his silence and appointed Dahlan to high-level positions? How do we know that Abbas did not know about it?”

Salah el-Bardawil, another Hamas leader, also called for an investigation into the truth of Abbas’ statements.

Dahlan, who has lived in the United Arab Emirates since being ousted from Fatah over corruption allegations, wrote on his Facebook page Thursday that Abbas’s speech was “full of lies and deception.”

Fatah is known for epic internal feuds, but Abbas’s speech marked the first time he entered the fray so publicly.

Abbas said Dahlan would never be allowed to return to Fatah and suggested there is no room in the party for those still loyal to the former Gaza strongman.

Abbas’s offensive against Dahlan could backfire by drawing new attention to long-standing allegations of top-level corruption in the Palestinian leadership.

In his speech, Abbas lashed out at Dahlan and hinted that he was also involved in the death of Yasser Arafat. Abbas also claimed that Dahlan, along with Khaled Islam, a former economic adviser to Arafat, and ex-PA minister Hassan Asfour, acted as spies for Israel.

“The three spies,” Abbas dubbed the trio in his speech. He said his knowledge of Dahlan’s involvement in the assassination of Shahedeh stemmed from an incident during a meeting of PA security officials in Ramallah in 2002. Abbas also revealed information pertaining to the ties between Dahlan and Israeli leaders.

The relationship between Dahlan and Abbas has reached an unprecedented low in recent months. Dahlan instigates against Abbas from the Gulf and has accused him of corruption. In response Abbas and PA security forces have gone after those loyal to Dahlan and have driven them from the ranks of Fatah.

There was a reconciliation effort between the two sides last month, when the Palestinian information minister Majed Faraj met in Amman with Samir Masharawi, a close associate of Dahlan. According to Faraj, Abbas agreed that Dahlan’s associates and loyalists in exile could return to the West Bank, but not Dahlan himself.

Abbas banished Dahlan in 2010, after Dahlan purportedly called him weak and criticized Abbas’s two adult sons. Dahlan has since spent his time shuttling between Egypt and the United Arab Emirates.

In an interview with The Associated Press last month, Dahlan spoke of his aid projects in his native Gaza Strip and in Lebanon, fueled by millions in Gulf aid dollars that are his to distribute. He described his close ties with Egypt’s military leaders and spoke of his conviction that Abbas had left the Palestinian national cause in tatters.

Dahlan said at the time he was “not looking for any post” after Abbas retires, but called for new elections and an overhaul of Fatah.

Abbas was elected in 2005, but overstayed his five-year term because a split between Fatah and the Islamic extremist Hamas, which seized Gaza from Abbas in 2007, prevented new elections.

Abbas has not designated a successor or said when he might retire, and there is no clear contender. A Fatah party conference where a new leadership would be elected is due in August, but it remains unclear whether it will take place.

In his speech to Fatah, Abbas claimed that in Arafat’s final years, Dahlan pushed to have the Palestinian leader replaced. Arafat died in November 2004, after a sudden illness, and some in the Palestinian leadership claim he was poisoned in a plot hatched by Israel. Israel has denied involvement.

“Who killed Yasser Arafat?” Abbas asked. “This [description of Dahlan's actions] is not proof, but it is a hint that deserves to be looked into, specifically since we are thinking about who gave the poison to Arafat.”

Dahlan said Thursday he will “uncover all the lies, particularly concerning the assassination of Yasser Arafat.”