TEL AVIV, JERUSALEM

Israeli army reservists have joined the fresh military campaign aiming to root out as they say Palestinian 'terrorist'.

Around 20,000 men in their 30s and 40s donned old uniforms in a mobilization not seen since the Gulf War.

Ariel Sharon says the army operation will last several weeks or months.

For those likely to see active duty in a region locked in tit-for-tat violence the justification for action is clear, an Israeli soldier telling reporters, "We have to fight back for what he did for the last months, the last period, all the terror attacks. We have to defend ourselves."

The Jewish reservists are responding to Sharon's call for unity in what he described as an "all out war on terrorism."