Tunisian President Beji Caid Essibsi on Saturday declared a state of emergency in the country, a week after 38 tourists were killed in an attack on a holiday resort, state news agency TAP reported.Essibsi was to address the nation later Saturday, the agency said without giving details.Last week, a gunman opened fire on sunbathers in the coastal city of Sousse, perpetrating Tunisia's worst-ever terrorist attack.Authorities identified the attacker as Seifeddin Rezgui, a Tunisian student, who was killed by police.The Islamic State terrorist group, which is active in Syria and Iraq, claimed responsibility for the attack.In March, gunmen killed 21 tourists and a policeman in an attack on the Bardo Museum in the capital Tunis.