To the best of my knowledge, no NATO signatory has been attacked by ISIS/ISIL/IS.
Jewish Museum of Belgium shooting
On 24 May 2014, a gunman opened fire at the Jewish Museum of Belgium in Brussels, Belgium, killing four people.
On 30 May, Mehdi Nemmouche, a 29-year-old French national of Algerian origin, was arrested at Marseilles in connection with the shooting. He is believed to have spent over a year in Syria and had links with radical Islamists and appears to have recorded a video bearing the flag of the rebel group Islamic State in Iraq and Syria.