Tunisia's president says the country is "not safe" from further extremist attacks and has declared a national state of emergency to avoid what he says is a risk of collapse.

President Beji Caid Essebsi's speech Saturday came just over a week after a gunman at the popular beach resort of Sousse attacked foreign tourists, killing 38 people.

Essebsi said the state of emergency would last 30 days.

Tunisia was previously under a state of emergency from January 2011, at the outbreak of the Arab Spring, until March 2014. It initially included a curfew and a ban on meetings of more than three people. Although those measures were relaxed, police and the military retained powers to intervene in unrest or for security reasons.