Hamas attack marks policy shift

By James Reynolds BBC correspondent in Jerusalem

The Erez border crossing is a forbidding area. From watchtowers, Israeli soldiers look out onto the wastelands of Gaza. Checkposts are shielded by concrete bollards.

At dawn each day, thousands of Palestinian labourers queue up at Erez to get to their jobs in the nearby industrial zone which is controlled by Israel.

Security is tight at the Erez border crossing

On Wednesday morning, after the main rush was over, a 21-year-old Palestinian woman joined the workers' queue.

According to reports, she made her way to the head of the line and set off the metal detector. She told Israeli security guards she had metal plates in her leg.

She was taken aside. Then, the reports say that she detonated the explosives she had strapped to her body, killing herself and those around her.

Her attack was swiftly claimed by both the Islamic movement Hamas and the al- Aqsa Martyrs' Brigades.

It was the first suicide bombing by Hamas for almost five months.

During this period, some Israeli officials believed the Islamic movement was obeying its own unofficial, undeclared truce.

But Hamas never declared a formal ceasefire in this time. The movement continued to fire home-made rockets from Gaza against Israeli targets.

And Israeli forces continued to go after members of Hamas.

First Hamas female bomber

The suicide attack at the Erez border crossing came with a message from the movement's founder Sheikh Ahmed Yassin - there is no Hamas truce.

The 21-year-old woman who killed herself at Erez was the first female bomber from Hamas.

Hamas had not declared an official ceasefire

Until now, the Islamic movement has always seen what it calls "martyrdom operations" as jobs for men.

For many years, the other Palestinian armed groups also believed that women should not be sent to carry out suicide attacks.

But that changed in January 2002, when a young ambulance worker from Ramallah blew herself up in Jerusalem. After that, armed groups began to deploy women as suicide attackers, in the hope that they would find it easier to avoid Israeli security checks.

Now, two years later, Hamas has decided to go the same way.

It is worth noting that the bombing at the Erez crossing was claimed as the joint work of Hamas and the al-Aqsa Martyrs' Brigades - a group linked to the Palestinian leader Yasser Arafat's mainstream Fatah movement.

Observers in Gaza see this as an important sign. It is an indication that, despite the wide-ranging political differences and rivalries between Hamas and Fatah, there is extensive co-operation in the field between the different armed factions.