TEL AVIV ø Hamas has been deeply affected by the Israeli assassination of its latest leader, Abdul Aziz Rantisi.

A report by the Jaffee Center for Strategic Studies, entitled "Hamas After Rantisi," said the organization in the Gaza Strip has now come under the direct control of political bureau chief Khaled Masha'al. Authored by Israeli researcher Meir Litvak, the report cited Masha'al's orders to keep the name of Rantisi's successor secret as reflecting Hamas's operation difficulties.

"That threat, alone, will not cause Hamas to disappear as a serious political actor," the report said. "But it has already produced the unprecedented decision to act henceforth under anonymous leader, and that raises serious questions about how the movement can function in the public domain when its leaders' identities remain secret."

The report said the assassination of both Rantisi and Hamas founder Ahmed Yassin will not necessarily lead to an increase in Hamas attacks. Litvak said Hamas had the capability to stage a series of suicide bombings as early as 1994.

"Coming just three weeks after the liquidation of the former leader of Hamas in Gaza, Sheik Ahmad Yassin, the killing this weekend of his successor, Abdul Aziz Rantisi, is likely to have far-reaching implications for the balance of power within Hamas and for its relations with the Palestinian Authority," the report said.

The killing of Rantisi, the report said, could facilitate a Hamas-PA dialogue in advance of Israel's anticipated withdrawal from the Gaza Strip. The PA had long regarded Rantisi as a rival and his death could enable others to join the Palestinian government.

The death of Rantisi and Yassin was also expected to change the balance of power between the Hamas leadership in the Gaza Strip and that in Damascus. The report said Masha'al and his colleagues in Damascus had blocked Rantisi's attempt to inherit Yassin's authority.

The report compared Yassin to Rantisi, saying the former enjoyed a reputation of a Sunni leader in the Middle East. In contrast, Rantisi was an operative and his appointment to succeed Yassin was challenged within the Hamas organization in the Gaza Strip.

Unlike Yassin, Rantisi consistently rejected any arrangement with Israel. The report said Rantisi expanded Hamas ties with Hizbullah and Iran.

"It may even be the case that what really determines the level of Hamas operations are its operational capabilities at any given time and the anticipated degree of public support, and that reactions to targeted killings by Israel are a minor consideration," the report said. "For example, there has been an appreciable decline in Hamas operations in the West Bank in the last three months, during which large numbers of leaders and operatives have been arrested or killed."