European Union diplomats have been finalising details of their decision to put the political wing of the Palestinian militant group Hamas on its list of terrorist organisations.
Hamas said its attacks were revenge for Israeli air strikes
EU diplomats said that Hamas would be named as a whole - unlike a recent move by the United States which named individual leaders or charities suspected of fundraising for Hamas.
EU foreign ministers announced at informal talks at the weekend that they had decided to include Hamas on their list.
Hamas' military wing, the Ezzedin al-Qassam Brigades, was blacklisted last year.
But some EU members - notably France and Germany - had until now opposed including the political wing as they argued that it could be counterproductive for the Middle East peace process.
On Monday, Hamas claimed two suicide attacks in Israel in which 15 people died. The group described them as revenge for an Israeli attempt to assassinate a top Hamas leader.
The decision requires all 15 member states to freeze Hamas assets and opens the way to prosecute the group's members.
Details will be published on Saturday.
Cristina Gallach, the spokeswoman for EU foreign policy chief Javier Solana, said: "This is an unequivocal message from the EU that terrorism will achieve nothing in the Middle East,"
"What has happened since August, when Hamas broke seven weeks of ceasefire, was absolutely unacceptable," the spokeswoman said.
"Hamas leaders know that if they reverse their position, renounce violence and enter the political process, they can come off the list."