In Cairo, the U.S. Embassy returned to full staffing Sunday, a spokesman said, for the first time since Tuesday protests against an anti-Islam movie made in the United States sparked turmoil across the Muslim world. But the American diplomatic presence remained reduced elsewhere in the region, meaning that there were fewer routes to repair relations even as they came under the most strain since the wave of democratic change caused last year by the Arab Spring.

In Tunisia, where additional security has been deployed to protect the embassy, the Saturday decision to withdraw non-essential U.S. embassy staff from the mission there appeared to jar Tunisian officials, who have marketed the country as a model of democratic transformation after the peaceful toppling last year of longtime president Zine El Abidine Ben Ali. Tunisia’s 2011 protests set the rest of the Arab world afire — and led, in the end, to newfound freedoms for many citizens to express their distaste for their own governments and for the United States…

In an address to the nation Friday night, Tunisian President Moncef Marzouki condemned that day’s violent attack on the U.S. Embassy and an American school, in which four protesters were killed. He said those who organized the protest — widely described here as religious hardliners known as Salafists — had “crossed a red line.” Yet he also sought to appease the sentiments of those reportedly angered by the film, “The Innocence of Muslims,” saying Tunisia would work with Egypt to sue its producers.