SOUSSE, Tunisia — Tunisia's Prime Minister Habib Essid on Saturday called for all citizens to work together to defeat terrorism as thousands of tourists prepared to leave the North African country in wake of its worst terrorist attack ever. Tourists crowded into the airport at Hammamet near the coastal city of Sousse where a young man dressed in shorts on Friday pulled an assault rifle out of his beach umbrella and killed 39 people, mostly tourists. “The fight against terrorism is a national responsibility,” said a visibly exhausted Essid at a press conference in Tunis early Saturday. “We are at war against terrorism which represents a serious danger to national unity during this delicate period that the nation is going through.” He announced a string of tough measures to fight extremism, including examining the funding of organizations suspected of promoting radicalism, closing some 80 mosques outside government control and declaring certain mountainous zones military areas. He identified the shooter, who was killed by police after the attack, as Seifeddine Rezgui, a young student at Kairouan University. The Tunisian Ministry of Health has confirmed the nationalities of 10 of the 39 victims of the terror attack in the beach resort town Sousse. It said Saturday they included eight Britons, a Belgian and a German. — Agencies