By Roger Hardy BBC Middle East analyst

After two days of confusion, the Palestinian leader Yasser Arafat has succeeded in removing one of his top security officials, Jibril Rajoub.

Mr Rajoub, head of security in the West Bank, had initially refused to go.

His sacking is part of Mr Arafat's reorganisation of Palestinian institutions in response to criticism from the United States and Israel.

But Mr Arafat is struggling to recover from the body blow he suffered in June at the hands of George W Bush.

Will Yasser Arafat find himself all alone, as the US wants?

The centrepiece of the American president's policy statement on the Middle East was a blunt call for a new Palestinian leadership - one that was, as he put it, "uncompromised by terrorism".

Even though the speech received mixed reviews, it has left Mr Arafat more beleaguered than ever.

Having enjoyed an unprecedented warm relationship with President Bush's predecessor, Bill Clinton, he has found himself rudely cast out into the cold by the American superpower.

Characteristically, he has responded with a flurry of activity designed to buy time and deflect criticism.

Overseas demands

Having already reshuffled his cabinet, he has called presidential elections for January 2003 - and has set about purging and reorganising his security apparatus.

This is one of the main demands of the Americans and the Israelis.

Yasser Arafat, under constant pressure, will be 73 next month

They insist that, to show he is serious about curbing Palestinian violence, he must replace his multiplicity of security agencies with a single unified command.

That has meant challenging some well-entrenched vested interests.

Until recently, the two most powerful security chiefs were Mohamed Dahlan in Gaza and Jibril Rajoub in the West Bank.

New security chiefs

But both have fallen out with Mr Arafat, and he is now creating a new security apparatus without them.

Mr Dahlan did not wait to be pushed; he resigned.

In recent interviews given in London, he has declared that despite his differences with Mr Arafat he has no intention of running against him in next year's elections.

Jibril Rajoub: was he sacked to appease President Bush?

Now, two other senior figures - Mr Rajoub and the Gaza police chief Ghazi Jabali - have been sacked.

Both had initially dug their heels in, feeling no doubt they were being made scapegoats to appease President Bush.

The affair showed up the disarray within Palestinian ranks.

But there is no immediate threat to Mr Arafat's position.

On the contrary, President Bush's speech has, perversely, strengthened him.

Any would-be challenger would be branded an American stooge.

Master of survival

What is in question is not Yasser Arafat's grip on power, but his credibility.

Throughout his long political career, he has escaped one crisis after another - including many of his own making.

He has always been tactically shrewd and a master of the art of survival.

His gamble is that he can consolidate his position ahead of next year's elections - and then confound President Bush by getting re-elected.

Pressures grow

But much can happen before then.

The pressures the Palestinian leader faces are more intense than any in the past.

Mr Bush has hit him where it hurts, wounding his international legitimacy.

He is under constant military pressure from his old adversary, Israeli Prime Minister Ariel Sharon.

And finally, he is older and frailer than he was; he will be 73 in August.

To believe he can go on defying the odds, escaping from every tight corner, until the bitter end may prove his ultimate undoing.