"Hamas has decided not to take part in a cabinet of national unity, but the movement insists that a unitary national committee be set up to supervise the Israeli withdrawal from Gaza," Mushir al-Masri, a spokesman of the Palestinian resistance group, said on Monday.
Hasan Yousef, the head of Hamas' political wing in the West Bank, said on Sunday that it was not the right time to join forces with Palestinian leader Mahmoud Abbas' dominant Fatah faction inside the Palestinian Authority (PA).
He said Hamas would rather await the outcome of legislative elections that are scheduled for January.
"We are not interested in being in the PA just for the sake of it," Yousef said. "We believe that the right way to do it is through elections."
"We are not interested in being in the PA just for the sake of it"
Hamas West Bank spokesman
Having boycotted previous elections as a result of its rejection of the 1993 Oslo autonomy accords that brought about the creation of the PA, Hamas decided this year to contest parliamentary elections.
Abd Allah al-Ifranji, a member of Fatah's central committee, told Aljazeera on Tuesday: "We hoped that our brothers in Hamas movement would agree on the formation of a Palestinian national unity government, as this step is necessary for all of us.
"A Palestinian national unity government eases our attempts to take united steps after the Israeli withdrawal from the Gaza Strip, and guarantees a halt of chaos after and during the Israeli withdrawal," al-Ifranji said.
"When we discussed this issue at Fatah's central committee's meeting in Amman, our goal was to have a Palestinian national group agreement, which results from the formation of a national unity government," he added.
"We are very sorry for Hamas' reaction and refusal of Fatah's offer," he said.
A strong Hamas showing in municipal elections in May has increased its hopes of a major breakthrough in parliament and of denting Fatah's dominance.
On Friday, Hamas said it was ready to work with the PA to prepare for Israeli withdrawal from the Gaza Strip that is due to be launched in mid-August.
Fatah called last week for all Palestinian factions to join a government of national unity to oversee the pullout.