The UN Security Council has condemned the Tunisia museum attack, saying no terrorist action can reverse the country's path toward democracy.
Seventeen foreign tourists and two Tunisians were killed when gunmen stormed the Bardo museum inside the heavily guarded parliament compound in central Tunis on March 18.
Security forces later killed two militants in an operation to free captives inside the museum.
At least two militants reportedly escaped.
Tunisian President Beji Caid Essebsi said in a televised speech that Tunisia is in a war against "terror."
U.S. Secretary of State John Kerry joined leaders from Europe condemning the attack and said Washington continued "to support the Tunisian government's efforts to advance a secure, prosperous, and democratic Tunisia."
Several Islamist militant groups have emerged in Tunisia since the 2011 uprising to oust autocrat Zine El-Abidine Ben Ali.