Domestic terrorism increased significantly in Greece in 2009, following large-scale rioting in December 2008. In 2009 there were more than 430 security incidents – defined to include incendiary and explosive attacks, as well as attacks involving small arms, grenades, and other infantry-style weaponry – far more than have been recorded in each of the previous 20 years. Local extremists increasingly targeted businesses and Greek law enforcement, and there was an increasing use of infantry-style weaponry in terrorist attacks.

The leftist domestic terrorist group Revolutionary Struggle claimed responsibility for shooting police officers and bombing financial targets, including U.S.-affiliated banks and the Athens Stock Exchange, which was targeted in an ammonium nitrate car bomb attack on September 2. A previously unknown group, Sect of Revolutionaries, emerged during the year to claim responsibility for attacks on police and other targets, including the only such lethal attack during the year: the June 17 murder of a police officer on protective detail outside the apartment building of a government witness in Athens. On October 27, unknown assailants attacked the Aghia Paraskevi police station in suburban Athens with AK-47s, seriously wounding six officers and a civilian. Two groups, the Guerilla Group of Terrorists and the Conspiracy of Fire Nuclei (SPF), jointly claimed responsibility for the December 27 bombing of the National Insurance Company building in Athens.

The appeals of eight convicted members of the November 17 terrorist organization went before the Supreme Court in October. Prosecutors urged the court to sustain the convictions, but recommended consideration of reduced sentences for two of the convicts. On December 3, an appeals court threw out the convictions of three members of the People’s Revolutionary Struggle terrorist organization who had initially been sentenced in 2004 to 25 years each for the 1994 murder of a police officer, 48 attempted murders by bombing, and 42 bomb attacks and attempted bombings, though they had been released for health reasons and on other grounds pending appeal in separate decisions in 2005 and 2006.

Throughout the year, self-styled anarchists attacked banks, police stations, the homes and offices of politicians, and other “imperialist-capitalist” targets with tools such as firebombs and Molotov cocktails. Since these attacks usually occurred outside normal business hours, few persons were seriously injured and there were no deaths. Several U.S. businesses were targeted. On January 10 , a rock-throwing group of pro-Palestinian demonstrators caused some physical damage to the U.S. Embassy during a protest against the Israeli operation in Gaza.

Greece is increasingly an EU entry point for illegal immigrants coming from the Middle East and South Asia and there was concern that it could be used as a transit route for terrorists travelling to Europe and the United States. The number of illegal immigrants entering Greece, especially through the Aegean Sea, increased dramatically in 2008 and 2009, with more than 100,000 illegal immigrants, nearly half of whom originated from North Africa, the Middle East, and South Asia, arrested each year. Greek authorities participated in the Container Security Initiative and cooperated with U.S. officials on information sharing, as well as the training of Greek security and customs officials, and judicial personnel. Greece sustained its participation in the International Security Assistance Force in Afghanistan by providing engineers and other support officers.