Exiled Hamas chief Khaled Meshaal said reconciliation between Fatah and Hamas must be based on jihad ("holy" war) against Israel.
"The first step [to liberating Jerusalem] is refusal to negotiate with Israel," Meshaal told participants at an al-Quds conference in Sudan on Sunday, adding that reconciliation between the two factions is "to establish a new, reconciled Palestinian position based on jihad," AFP reported.
Meshaal said the uprisings in Tunisia and Egypt have injected new life into Hamas.
"Today we are witnessing Cairo returning to its natural state, after it disappeared from that state for a long time," the Damascus-based Hamas chief said.
Meanwhile in Gaza, Hamas spokesman Sami Abu Zuhri said Saturday the Islamist group is preparing "a comprehensive initiative" to bring reconciliation between the two factions.
"We are preparing a comprehensive national initiative that aims at rearranging the Palestinian internal situation to regain the national unity," Zuhri said.
Last month, Fayyad offered to travel to Gaza to discuss the issue, reportedy telling Hamas it could retain control of the Strip. But the Islamist group rejected Fayyad's offer, calling him a puppet of the U.S. and Israel.
In March 2007, the P.A. formed a unity government following a Saudi-initiated meeting in Mecca aimed at reconciling the two factions.
Three months later, Palestinian Authority President Mahmoud Abbas dissolved the coalition after Hamas took control of the Gaza Strip in a bloody military-style coup.
Within days, Abbas formed an emergency government and appointed Salam Fayyad to replace Gaza-based Hamas chief Ismail Haniyeh as prime minister.
Efforts by Egypt and others over the past three years to convince the two factions to reconcile never succeeded.
Since gaining control of the Strip, Hamas has steadily tightened its control over the 1.4 million residents, imposing sharia (Islamic) law in the schools, courts and public places.
Haaretz contributed to this report.