Nabil Abu Rdaina, a senior aide to Arafat, said on Saturday the 75-year-old leader was still in a serious condition at the French military hospital where doctors have been unable to determine what is wrong with him.
"The doctors say his condition is not irreversible. There is no change, he is still in a critical condition. The doctors still do not know what is wrong with him," Abu Rdaina said.
YNET, the website of leading Israeli daily Yediot Ahronoth, earlier quoted Palestinian sources as saying Arafat had partially emerged from a coma and was communicating with doctors. Rdaina did not comment on that report.
Conflicting reports on Arafat's health have emerged since he was rushed into the hospital's intensive care unit on Wednesday night, with many in his close circle concerned that the news about his health might increase chaos back home.
A row is also brewing over where Arafat, who personifies the Palestinian struggle for an independent state, might be buried.
Palestinian officials have refused to discuss funeral preparations openly, but Arafat has said he wants to be buried in Jerusalem. Israel wants Arafat, admired by Palestinians but reviled by many Israelis, to be buried in the Gaza Strip.
The death of a Palestinian leader Israel and Washington see as an obstacle to peace could alter the dynamics of the Middle East conflict.
Ordinary Palestinians praying at mosques on Friday with fading hope for Arafat's life made clear they wanted a successor even less willing to compromise with Israel in the battle for a state.
Few in Gaza or the West Bank seemed to seek the kind of replacement for the 75-year-old ex-guerrilla who might be favoured by Israel or its US ally - a moderate ready to give ground and end a four-year-old uprising.
Moderate PA figures may not be
able to command mass support
"Unless a successor is more determined and steadfast on the fundamental Palestinian rights, he will never be trusted by the people," 30-year-old Khalid Ammar said at a Gaza mosque.
"Palestinians need to rely more and more on their resistance to the occupation and not on negotiations."
Arafat has named no successor in public.
Most official functions have been taken over - for now - by Prime Minister Ahmad Quraya and former prime minister Mahmud Abbas, both leading moderates. His constitutional successor would be parliament speaker Ruhi Fattuh.
But none of the three has great popularity or could easily either persuade Palestinians to make a difficult compromise with Israel or crack down on armed factions to revive long-stalled peace talks.
"With Arafat's death, chances of reaching peace will be less. He is the one who enjoys charisma and the others don't," 37-year-old Muna Ibrahim, a mother of five in Ram Allah in the West Bank, said.
Israel's Maariv newspaper said Arafat had written a will calling for Palestine Liberation Organisation Foreign Minister Faruq Qaddumi to replace him.
"With Arafat's death, chances of reaching peace will be less. He is the one who enjoys charisma and the
resident of Ram Allah
But Quraya denied there was any will. Qaddumi, based in Tunis, has also not set foot in Palestinian territories for years because he opposes the 1993 interim peace accords, agreed by Arafat, that gave Palestinians a measure of self-rule.
The accords allowed Arafat to leave exile, seeking a state on land captured by Israel in the 1967 Middle East war instead of Israel's removal - which he had first fought for and which Islamist factions such as Hamas still do.