Tunis Washington on Sunday urged Tunisia to bring the attackers of its embassy here last month to trial and pledged to continue support for the democratic transition in Tunisia, the cradle of the Arab Spring.
"I call upon the Tunisian government to conduct its investigation and bring the perpetrators and instigators of this attack to justice," U.S. Ambassador Jacob Walles said in a letter to Tunisians marking a month after the attack on the U.S. Embassy in Tunis.
Salafists attacked the embassy last month to protest a film made in California deemed offensive to Islam. At least four people were killed when they stormed the embassy.
In a recording posted to Islamist websites on Friday, al Qaeda leader Ayman al-Zawahiri called on "free and distinguished zealots for Islam" to "continue their opposition to American crusader Zionist aggression against Islam and Muslims" around the region.
Walles called upon the Tunisian government "to provide security for its citizens and guests," adding that relations between the two countries would not be affected by the attack.
"These attackers were unable to damage the strong link between two peoples and U.S. commitment to support the transition in Tunisia from a dictatorship to a democracy, free and tolerant," he said.
Tunisia expects Washington to guarantee around a fifth of its $2.2-2.5 billion borrowing needs next year to help its economy recover from last year's revolution, the country's minister of international cooperation, Riadh Betaib, told Reuters last month
The U.S. ambassador's message comes while Tunisia is preparing to try Abu Ayoub, a senior leader in the Salafist movement in Tunisia next week on charges of disturbing public security and incitement to violence, including the U.S. Embassy attack.
The government-led Islamist Ennahda movement arrested dozens of Salafists after the embassy attack. Lawyers said the detainees would be tried under an anti-terrorism law.
Lawyers said this week some Salafists had started a prison hunger strike to protest ill-treatment and prison conditions.
U.S. President Barack Obama vowed last month to tighten security at diplomatic missions around the world after the killing of the U.S. ambassador to Libya and attacks on embassies in Tunisia, Yemen and Egypt.
(Reporting By Tarek Amara; editing by Todd Eastham)