Khaled Meshaal, who lives in exile in the Syrian capital, Damascus, was speaking in Egypt on Sunday where progress on the exhange of prisoners with Israel was also discussed.
"No presidential or parliamentary elections can be carried out without harmony and reconciliation," Meshaal said in the Egyptian capital, Cairo.
"We dismiss any suggestions that the elections will be carried out on the status quo where Gaza will be ruled out and the elections will be carried out in the West Bank... We warn of any hasty decisions of the proposals made by Israel and the US."
Hamas won elections in January 2006 but was shunned by the world powers, worsening a power struggle between the Palestinian factions.
Hamas presently controls the Gaza Strip, which it seized in 2007 after a series of deadly clashes with Fatah security forces. Fatah, led by Mahmoud Abbas, the Palestinian president, is based in the West Bank.
Source: Al Jazeera (English)