On Tuesday, Mahmoud Abbas, the Palestinian prime minister, canceled a planned meeting with his Israeli counterpart, Ariel Sharon, after coming under sharp criticism from Mr. Arafat and other Palestinian officials who contended that he had botched negotiations with Israel. 

Since then, while Mr. Abbas has largely withdrawn from public view, his allies have said that Israel must advance the peace efforts by making concessions — like releasing large numbers of Palestinian prisoners — that might strengthen Mr. Abbas's political standing.

But in advance of a visit to London on Sunday, Mr. Sharon said that Mr. Arafat was obstructing peace and that European leaders were making "a major mistake" by dealing with him. 

"Every act of this nature only postpones the progress in the process," Mr. Sharon said in an interview with The Daily Telegraph. He said that the effect was to undermine Mr. Abbas. 

Israeli officials said that, in recent contacts with the Bush administration, the Israeli government had said it might reconsider its policy of not arresting or deporting Mr. Arafat if he interfered with Mr. Abbas, known as Abu Mazen. 

"If Arafat continues to attempt to scuttle the peace process and undermine Abu Mazen and his government, we will have no other recourse than to reconsider and discuss again the question of Arafat's status and position," said a senior official in Mr. Sharon's office.

For more than a year, the Bush administration has joined Israel in refusing to deal with Mr. Arafat. Under American, Israeli, and European pressure, Mr. Arafat reluctantly appointed Mr. Abbas prime minister this spring, and the Palestinian parliament confirmed him. 

Though he had worked with Mr. Arafat for decades in the Palestinian leadership, Mr. Abbas was a critic of the armed Palestinian uprising. The Israeli and American governments embraced him as the alternative leader they were seeking.

Mr. Abbas has been careful to consult regularly with Mr. Arafat, but tension has increased between them as an American-backed peace plan has moved ahead. The tension burst into the open this week as Mr. Arafat and his allies accused Mr. Abbas of gaining almost nothing from Israel in exchange for an agreement two weeks ago by the main Palestinian factions to suspend violence.

While Mr. Abbas has strong international support and Mr. Arafat is shunned by the United States and others, Mr. Arafat has strong support among Palestinians, and Mr. Abbas risks being seen by them as an Israeli and American agent. Further isolating Mr. Arafat would only enhance that image, said Hisham Ahmed, a political scientist at Bir Zeit University in Ramallah.

"If Sharon tightens the siege and the isolation of Arafat, people will point the finger at Abu Mazen and his government," Mr. Ahmed said. Already, he said, "People constantly mock Abu Mazen and his government on the street."

He said that "the only one who could enable Abu Mazen to succeed is Sharon," listing steps like releasing Palestinian prisoners and removing Israeli military roadblocks.

Under the peace plan, Israel has withdrawn from parts of the Gaza Strip and most of the West Bank city of Bethlehem. It has said it will not pull back from other Palestinian areas until Mr. Abbas acts to suppress militant groups and collect their weapons. After a series of suicide bombings last year, Israel reoccupied Palestinian cities in the West Bank that it had ceded to Palestinian control.

Israel has also released about 280 Palestinian prisoners, and it says it is preparing to release some 300 more. Israel is not required by the peace plan to take that step, which is politically sensitive within Israel, but Mr. Sharon says he believes it will strengthen Mr. Abbas.

Muhammad Dahlan, Mr. Abbas's minister of security, told Israeli officials on Thursday that to help Mr. Abbas and the peace plan they must release many more of the roughly 5,800 prisoners they hold. 

But the senior Israeli official said that any such step would be meaningless unless Mr. Arafat was stripped of all authority. "Even if you release all the prisoners and Arafat remains in position, nothing will happen," the senior Israeli official said. "He will take credit."

Mr. Sharon has said in the past that he was prevented from acting to deport Mr. Arafat by a pledge made to President Bush not to harm the Palestinian leader.