By the BBC's Paul Wood

Hopes of bringing peace to the Middle East now largely depend, as so often in the past, on the enigmatic personality of Yasser Arafat.

Under siege from without and from within, he remains the dominant force in Palestinian political life, indispensable for American plans in the region.

America has given public support to a Palestinian state

Mr Arafat knows that maintaining a ceasefire between Israel and the Palestinians is vital to American hopes of building a wide coalition against terror, including the moderate Arab states.

That is why the Americans are courting him, declaring in more explicit terms than ever before that a fully-fledged Palestinian state is the key to peace in the Middle East.

The Palestinian leader is responding in kind. Fearful of the risks of being caught in the crosshairs in President Bush's war on terror, he has repeatedly issued orders to those on his own side to put their guns away.

The leadership declares it has taken and will take the appropriate measures on the Palestinian side to put a quick and decisive limit to any violation from our side

Yasser Arafat

"The leadership declares it has taken and will take the appropriate measures on the Palestinian side to put a quick and decisive limit to any violation from our side," he said.

That particular statement was issued in an attempt to salvage the joint ceasefire in the wake of an attack by Palestinian gunmen on an Israeli settlement in which a young couple died - the first Jewish civilians to be killed in Gaza since the truce.

The Israeli press has reported that some in the army are intent on removing Mr Arafat - a report denied by Israeli Foreign Minister Shimon Peres.

Mr Peres said that without Mr Arafat, a much more hardline Palestinian leadership could take charge, possibly drawn from Hamas, one of the groups which has repeatedly sent suicide bombers onto Israeli soil.

Militants' popularity grows

It is true that militant groups, such as Hamas and Islamic Jihad, have grown in popularity over the course of the year-old Palestinian uprising, the intifada.

Islamist militant groups have grown in popularity during the intifada

In Gaza, Palestinian police buildings were surrounded by angry mobs when Mr Arafat's security forces tried to arrest those accused of breaking the ceasefire by attacking Israeli army positions.

Such incidents do not mean his leadership is threatened. But they do point to the main factor constraining Mr Arafat's freedom of action - the anger on the Palestinian streets, and the continued desire of the majority of Palestinians to carry on with the intifada.

Mr Arafat could not call off the uprising without substantial political concessions of the kind the Israelis have yet to offer.

And until the intifada is concluded, Mr Arafat cannot act decisively against the militants who daily break the ceasefire.

Stop-start talks

Yasser Arafat has made a complete mockery of this ceasefire

Israeli spokesman Dore Gold

When the uprising is finally declared over, the Palestinian leader's security chiefs are confident that they can round up all the Hamas and Islamic Jihad militants who might threaten a deal - just as they did in the wake of the Oslo peace agreement in 1993.

But the Israelis want such action now: they have handed the Palestinian Authority a list of "terrorist suspects" to be arrested.

Those on the list are, the Israelis say, responsible for much of the continuing violence - and arresting them is seen as a test of Palestinian good faith.

"Yasser Arafat has made a complete mockery of this ceasefire," said Israeli spokesman Dore Gold.

In a reference to the stop-start peace talks, he added: "Until it becomes clear that Mr Arafat is willing to fulfil his ceasefire obligations, what point is there in pursuing this discussion?"

'Israel's Bin Laden'

The Israeli Prime Minister, Ariel Sharon, has called Yasser Arafat "our own [Osama] Bin Laden" heading his own "terrorist network".

Mr Arafat has replied that he is himself number one on Bin Laden's target list for having signed the Oslo accords.

That there is no obvious successor to Mr Arafat is one sign of a leadership style his detractors have called autocratic and secretive.

His long career - the journey from guerrilla leader to Nobel Prize winner - has always been marked by improvisation and a brilliant tactical sense.

These skills are being tested to the limit now as he is boxed in by the international community, the Israelis and the militants on his own side.

But there is no doubt that Mr Arafat remains in charge.