It had been reported that Qatar was arranging for Abbas and Mishaal to meet in Doha to discuss political differences and clear the way for the establishment of a national government.
Speaking to Aljazeera, Abbas said he was still willing to form a national unity government based on the detainees' document.
Commenting on Abbas's statement, Ismail Rudwan, a senior leader in Hamas, told Aljazeera that the only remaining difference was the Arab Peace Initiative.
"The only way to solve this problem would be through the detainees' document which stipulated acceptance of Arab and international legitimacy," he said.
Rudwan affirmed that Hamas was committed to the formation of a national unity government based on the document.
However, Ahmad Abd al-Rahman, adviser to the Palestinian president and spokesman for Fatah, denied that Hamas had accepted the detainees' document.
"Hamas has no alternative but to accept the legitimacy of the Palestine Liberation Organisation, the detainees' document and the mutual recognition with Israel, which constituted the basis upon which the Palestinian Authority and recurrent Palestinian governments were formed," he said.