A first rift appeared in the Palestinian unity government when Hamas accused President Abbas of illegally naming one of the Islamist group's long-time foes as national security adviser. In its first rift with Fatah since forming a Palestinian unity government, Hamas accused President Mahmoud Abbas on Monday (March 19) of appointing one of the Islamist group's long-time foes as national security adviser without consultation. Mohammad Dahlan, one of Fatah's most powerful leaders and a possible successor to Abbas as president, led a crackdown on Hamas Islamists as Gaza security chief in the 1990s. Dahlan served in past Palestinian governments and played a key role in past peace talks with Israel over the years. In recent months, Hamas accused Dahlan of trying to assassinate Prime Minister Ismail Haniyeh and of unofficially commanding pro-Fatah forces in fierce factional fighting before the unity government was sealed at the weekend. Some of the Fatah forces held training last month in an open territory near Gaza City. Hamas in a statement urged Abbas to go back to the law and to examine his decision to appoint Dahlan in accordance to the law. "This is a resolution toward that Mohamad Dahlan has to be the consultant of national security council to palestinian people does not depend on law and does not depend upon the agreement between Fatah and Hamas at Mecca agreement. We hope that President Abbas have to be evaluating this resolution again in order to support the solidarity and unity and to support all type of Mecca agreement toward stability of security agency and security situation here in Gaza and the West Bank," Fawzi Barhoum, a Hamas spokesman, told Reuters. The appointment of Dahlan to the security post was Abbas's first official act after swearing in the new government on Saturday, elevating his role in the chaotic security hierarchy at a time when both sides say they want to end internal warfare. The unity deal has largely stemmed the fighting, which killed more than 300 Palestinians in the past year, but tensions remain high. Abbas and Haniyeh settled on the appointment of Hani al-Qawasmi, an academic with no security experience, to serve as interior minister. But officials say Qawasmi is unlikely to wield much power. Abbas wants Dahlan to serve as top adviser and secretary of a new umbrella Palestinian National Security Council that will, in theory, oversee the divided security services. Palestinian officials and analysts say the fate of Hamas's Executive Force will be the most difficult issue to resolve. Hamas says it is pushing ahead with plans to double the size of the contingent to 12,000 members. Fatah wants the Executive Force to be dismantled or absorbed into the other services, which are dominated by Fatah. Dahlan is a favourite of the United States but it is unclear what direct role Washington will play going forward. An 86 million U.S. dollar American plan to train and equip Abbas's security forces has been put on hold because of congressional concerns about his power-sharing deal with Hamas. But some of the work is going forward using European and Arab funds, Western diplomats said.