The Islamic Hamas movement, which controls Gaza, said on Thursday that it cannot accept Salam Fayyad, the West Bank-based prime minister, to lead the upcoming Palestinian unity government.

Appointing Fayyad for the new government "is unacceptable and it cannot theoretically or practically lead to achieving reconciliation," said Mousa Abu Marzouk, the deputy chief of Hamas ' politburo.

Abu Marzouk said the unity government should replace Hamas' Gaza government and Fayyad's government in the West Bank. "We cannot talk about dissolving Haneya's government while keeping Fayyad as a prime minister," he added, referring to Hamas' Prime Minister Ismail Haneya.

It is the first time that Hamas announces openly its rejection to Fayyad to lead the government. Abbas wants Fayyad to be the upcoming premier due to his acceptance by the West to avoid international isolation of the government.

Meanwhile, President Mahmoud Abbas' Fatah party, Hamas' main rival, condemned Hamas' attempts to impose its stances prior to next week's meeting in Cairo to discuss the formation of the government.

A Fatah leader criticized Abu Marzouk's statements, adding that he should not talk this way in the media. "The positions should have been better announced on the table of dialogue, not through the media," said Hussien al-Sheikh of Fatah.

He noted that this issue would be discussed thoroughly when Hamas and Fatah meet on Tuesday.

Abbas assigned Fayyad, the western-backed economist, to lead the government in the West Bank after Hamas routed pro-Abbas forces and seized Gaza in 2007. Hamas has been ruling Gaza since then with its own administration.

On Tuesday, representatives of Hamas and Fatah will talk about the formation of a technocratic government in accordance with the Egyptian-brokered agreement that was signed early last month. The agreement is sought to end political split between Gaza and the West Bank.

The United States and most European countries classify Hamas as a terrorist organization for refusing to recognize Israel.