Al Qaeda leader Ayman al-Zawahri launched an attack on Hamas because of their attempts at reconciliation and dialogue with the Palestine Liberation Organization (PLO).
In a voice message, al-Zawahri criticized Hamas's declaration of principles and policies, in which it affirmed its commitment to the establishment of a Palestinian state on the "1967 borders."
Hamas has made clear that it considers any such Palestinian state to be a stage to the total destruction of Israel.
The Sahab Foundation, one of al-Qaeda's media outlets, broadcast Zawahri's speech which was titled "Palestine does not support traitors."
He said Hamas tried to use two contradictory policies, one for the Muslims where it says, "We are against Oslo," and others to the West, where they say, "We are participants in the Oslo agreement." (As far as I know, Hamas has never said that, although when it was in the government with Fatah it said it would respect existing agreements. This is a long time ago.)
The last time Al Qaeda attacked Hamas, in 2008, it was for it attacking civilians!