Rajoub is seen as a kingmaker in any Palestinian succession

Some reports said Mr Arafat drew his pistol and pointed it at the astonished security chief, while both men's bodyguards also drew their weapons. Colonel Rajoub was then allegedly dragged from the room.

Israel radio quoted senior members of his Preventative Security force as saying a "sharp row" did occur on Monday, although they denied Mr Arafat threatened Colonel Rajoub or slapped him, as Israeli press reports alleged.

Mr Rajoub himself has denied any hint of a dispute, and in comments published in the Palestinian press he said the story was circulated by "hostile elements".

You are repeating their big lies... they have destroyed all our prisons, and you are coming to ask me these bad questions, and wrong questions. Be fair

Yasser Arafat to the BBC's Lyse Doucet

Yasser Arafat, he said, was the symbol of the Palestinian national struggle and any dispute with him would be the peak of treason.

The alleged incident is said to have occured after a mob of 300 Palestinians swarmed into the central jail in Hebron in the West Bank and released 17 prisoners, including Islamic Jihad leader Muhammad Sidr.

Another mob was reported to have tried to free prisoners in Gaza, after Israeli attack helicopters and F-16 warplanes had bombed the compound where they were held, but was driven back after security officers fired into the air.

The leader's mood has fluctuated during media appearances

Mr Arafat is said to have accused Mr Rajoub of insubordination during their heated argument about the events, shouting that he was an "Israeli spy, CIA agent".

Mr Arafat has appeared to lose his temper at times during a recent spate of media interviews he has given from his office confinement.

In an interview with the BBC's Lyse Doucet last week, the Palestinian leader raged against the "big lies" repeated in the media that the Palestinian Authority was not committed to clamping down on the militants behind attacks Iaunched against Israeli civilians.

However, at other times Mr Arafat seemed calm and upbeat, even dismissing the effectiveness on Israel's blockade of his HQ.

Israel's tanks have encircled Arafat since mid-December

On Tuesday UN Secretary General Kofi Annan became the latest leader to condemn what he called Israel's "virtual house arrest" of Yasser Arafat and appealed for it to be lifted.

Israel says Mr Arafat must first arrest the assassins of an Israeli cabinet minister in October and detain other militants involved in the uprising.

However, Israeli Prime Minister Ariel Sharon has since declared Mr Arafat "irrelevant" and said he could never again be Israel's partner in future peace negotiations.