"Hamas must renounce its control over Gaza and Abu Mazen (Palestinian president Mahmud Abbas) must stop talking to Israel so that comprehensive Palestinian negotiations can be opened," he said in a speech at the Yarmuk refugee camp near Damascus.
"Hamas must cease its armed hegemony over the Gaza Strip which is separated from the West Bank and Jerusalem," he said, referring to last June's Islamist takeover after Hamas ousted forces loyal to Abbas following a week of deadly fighting.
"The Palestinian Authority must turn its back on political coups d'etat and stop talking to Israel until the end of all Jewish settlements" on Palestinian land, Hawatmeh said.
He was addressing a meeting organised to mark the 39th anniversary of the DFLP, which he founded in 1969.
The DFLP was among three Palestinian factions which offered last October to mediate a settlement between Fatah and Hamas. A new initiative to resolve the conflict "will see the light of day very soon," Hawatmeh said.
"This dreadful conflict has destroyed the unified Palestinian national project. It has increased the despair of the Palestinian people and gived the enemy the chance to scoff at our rights."
The DFLP leader also called for the deployment of international troops on Palestinian land occupied by Israel since the 1967 Arab-Israeli war.
But he did not attend after the DFLP said his return should not be on the basis of just temporary permission - they wanted it to be unrestricted.