Tunisian authorities have arrested more than 20 suspected militants in a nationwide security crackdown since gunmen killed 23 people, mostly foreign tourists, in Wednesday’s attack in the capital.

Tunisia says it will deploy the army to major cities and arrested nine people after 20 foreign tourists were shot dead at a museum in the capital in an attack claimed by Islamic State.

Gunmen in military uniforms stormed Tunisia’s national museum yesterday, killing 18 foreign tourists and two Tunisians in one of the worst militant attacks in a country that has largely escaped the region’s Arab Spring turmoil.