Hamas rules the Gaza Strip, which it wrested from security forces allied with Palestinian President Mahmoud Abbas in five days of intense fighting in June. Abbas then kicked Hamas out of a unity government and installed his own, Western-backed administration. Abbas will represent the Palestinians at the conference next week in Annapolis, Maryland. Hamas is not invited.
"We realize that this conference was stillborn and is not going to achieve for the Palestinian people any of its goals or any of the political and legal rights due to them," Haniyeh said outside the Palestinian parliament building in Gaza City.
Haniyeh said Abbas did not have the mandate to make compromises in talks with Israel, especially over the demand of Palestinian refugees to return with their families to homes lost after Israel's creation in 1948.
"No one is authorized to compromise or to give up any of these rights, especially the right of return," Haniyeh said.
Haniyeh also called on Abbas not to cave in to a recent Israeli demand that the Palestinians recognize Israel as the home of the Jewish people.
"We do not recognize that this state is Jewish," Haniyeh said.
Other Palestinians object to the demand on the ground that it implies the Palestinians drop their demand to repatriate refugees.
A recent Palestinian poll by the independent company Near East Consulting found that 57 percent of Palestinians don't believe the conference will lead to progress in Israeli-Palestinian peacemaking. Just over 60 percent said they wanted Abbas to attend the conference.