Europol plays a key role in the fight against organised crime and terrorism, utilising its unique information capabilities and expertise to support the competent authorities of the EU Member States. Nearly ten years after the attacks of 11 September 2001, terrorism continues to pose a serious threat to the European Union and its citizens. In 2010, seven people died and scores of individuals were injured as a result of terrorist attacks in EU Member States., The fight against terrorism, therefore, remains a top priority for the European Union and for Europol. After the Organised Crime Threat Assessment (OCTA), the TE-SAT is Europol’s most significant strategic analysis product. It provides law enforcement officials, policymakers and the general public with facts, figures and trends regarding terrorism in the EU. It is a public document produced annually on the basis of information provided and verified by the competent authorities of the EU Member States., In some cases it remains difficult to differentiate between crime and acts of terrorism and extremism. EU Member States have agreed to regard terrorist acts as those which aim to intimidate populations, compel states to comply with the perpetrators demands and/ or destabilise the fundamental political, constitutional, economic or social structures of a country or an international organisation. The TE-SAT recognises that definition in the collection and reporting of its source data. In 2010, terrorist attacks took place in nine Member States. An increasing number of individuals were arrested for the preparation of attacks in the EU. Also, Member States prevented the execution of various attacks, including attacks by Islamist terrorist groups, which aimed to cause mass casualties.