Members of the Libyan Salafi armed group Ansar al-Sharia guard the gates of a main hospital to protect doctors from armed youths in Benghazi, September 20, 2012. (Asmaa Waguih/REUTERS)

Some are al-Qaeda operatives who saw fit to rebrand in the wake of last year’s Arab uprisings. Others are radical Islamists whose goal is to impose strict religious rule on a region in political transition. All are calling themselves Ansar al-Sharia — Partisans of Islamic Law.

The name has been adopted by new groups from Yemen to North Africa and appears to be the latest manifestation of radical Islam in a changing Middle Eastern order.

The appellation gained attention in recent weeks because Libya’s Ansar al-Sharia was blamed by the government for the attack on the U.S. Consulate in Benghazi, which left four Americans dead, including the ambassador.

But Ansar al-Sharia groups have emerged in Yemen and Tunisia over the past two years as a wave of revolutions spread through the region. Banners claiming allegiance to the name were also spotted in Egypt during the uprising last year.

Although relatively small, the groups — all espousing the ultraconservative Salafist strain of Islam — are widely seen as a worrying trend amid the freedoms unleashed after the collapse of dictatorships. They pose a challenge to fragile transitional authorities, including new moderate Islamist governments.

Analysts say the designation has appeared periodically before — the radical British cleric Abu Hamza al-Masri was the leader of a group called Ansar al-Sharia. But it has become more attractive at a time of political transitions, when there is opportunity to push for the Salafist agenda.

Omar Ashour, an expert on Islamist movements at the University of Exeter, noted that the name emphasizes support for Islamic law “when implementation of sharia is a possibility.”

Some observers have described Ansar al-Sharia as a new offensive by al-Qaeda under another name, designed to win back hearts and minds after the extremist network was sidelined by popular protests against authoritarian rule.

But while Yemen’s Ansar al-Sharia is believed to have been created by al-Qaeda, the North African groups do not appear to have a direct connection with the jihadist organization or share its global jihad agenda.

Ashour says the emerging groups are not part of a broader network but could develop organizational links. They all, however, subscribe to the ultraconservative Salafist ideology and are demanding changes to bring legal systems in line with sharia law.

In Libya, Ansar al-Sharia has denied the government’s accusations that it was behind the Sept. 11 military-style attack on the U.S. compound in Benghazi. But the brigade, which as founded after the toppling of Moammar Gaddafi’s government, admits it was involved in the destruction of Sufi shrines.

In Tunisia, a leader of Ansar al-Sharia, Hassan Brik, was taken in for questioning last week after parts of the U.S. Embassy compound there were vandalized in protests this month against the amateur video posted on YouTube that ridiculed the prophet Muhammad. The Tunisian group, which was founded in 2011 by an ex-jihadist, has been linked to violent protests against art festivals that the Islamists claimed tarnished their religion.

In Yemen, Ansar al-Sharia appeared in April as an apparent offshoot of al-Qaeda in the Arabian Peninsula, the Yemeni branch of the network.

Gregory Johnsen, author of the “The Last Refuge,” a forthcoming book on Yemen and al-Qaeda, says it was a “crude rebranding attempt.”

He noted that a chief cleric with al-Qaeda was the first to mention Ansar al-Sharia on a jihadist forum, saying that his organization carried so much baggage that it had decided to adopt a new name.

Yemen’s Ansar al-Sharia has released a video showing executions of individuals whom the group accused of helping Americans and Saudis with drone strikes, but its fighters have also been involved in providing services to areas that fell under their control, Johnsen says.

Aaron Zelin, a fellow at the Washington Institute for Near East Studies, says the rise of Ansar al-Sharia groups points to an end to al-Qaeda’s “unipolar” global jihad of the past decade, with jihadists acting locally, even if they think globally, and being more interested in providing services and governance.

“They are fighting in different lands using different means, but all for the same end, an approach better suited for the vagaries born of the Arab uprisings,” he wrote in Foreign Policy magazine.