It wasn’t until Sept. 19 that a top U.S. official, Matthew Olsen, head of the National Counterterrorism Center, called the incident a terrorist attack, but he added that there was as yet no evidence that it was planned in advance.

Investigators are looking into the possibility that the attackers had ties to extremists operating in Mali, where a military coup nine months ago effectively divided the country. The Islamist militants who seized control in the north are imposing a merciless interpretation of Islamic law, according to a report released last week by Amnesty International, the global human rights watchdog.

The Amnesty International report documented a string of human rights abuses, portraying a burgeoning Islamist emirate that’s reminiscent of Afghanistan under Taliban rule. More than 400,000 people have fled the north for refuge in the government-controlled central and south of Mali, or in neighboring countries, the report said.

“As Islamist groups consolidate their hold on the conquered territories, the number of corporal punishments (amputations, floggings, stoning to death) continues to grow,” the report states, adding that “these practices appear to be intensifying despite the demonstrations held by some segments of the local population who protested against such punishment.”

African leaders at the General Assembly raised concerns about Mali in their addresses and bilateral talks, though the issue didn’t carry the same urgency, at least publicly, as the civil war in Syria.

That could change now that U.N. Secretary-General Ban Ki-moon plans to name a special envoy for Mali, according to a U.N. summary of Wednesday’s meeting. The news will be welcomed by other African nations, which worried about spillover from the conflict and are urging the Security Council to intervene to restore order in Mali.

“Northern Mali has become a lawless area, used as a safe haven for recruitment and training by the international terrorist nebula, which wrongly uses Islam as a pretext to disguise its criminal activities, and seeks to attack foreign interests as well as reach other countries of the region and the world,” Senegal’s President Macky Sall told the assembly.

In her remarks, Clinton also raised the specter of a terrorist base with the capacity to carry out attacks across the globe, calling it “a threat to the entire region and to the world.” She pledged a stepped-up counterterrorism effort across the Maghreb and Sahel.

“And we’re working with the Libyan government and other partners to find those responsible for the attack on our diplomatic post in Benghazi and bring them to justice,” Clinton said.

Anouar Boukhars, an expert on extremism in North Africa, said that Clinton was overblowing the threat posed by al Qaida in the Maghreb, better known by the acronym AQIM, but she may have been doing so to generate greater international attention on the worsening situation in northern Mali and other parts of the region.

“I think it might be an exaggeration that (AQIM) is a threat to the whole world,” said Boukhars, who teaches at McDaniel College in Westminster, Md. “But there is a lot of concern about what is happening in the north.”

AQIM wasn’t alone in overrunning the north, he pointed out. It did so in an uneasy alliance with ethnic Touareg rebels and Malian Islamist extremists who may not share AQIM’s regional aspirations.

The fear, he said, is that the longer the situation persists, the more time AQIM will have in which to forge “operational” links with like-minded extremists in neighboring countries, further destabilizing an already deeply unsettled region.

“There has to be a political solution very quickly because the threat of radicalization exists,” Boukhars said, adding that he’d seen no evidence of cooperation between AQIM and Ansar al Shariah, the group in Benghazi suspected in the consulate attack. The group’s leaders deny involvement.

Clinton’s characterization of AQIM appeared to go beyond a U.S. intelligence community assessment that was presented in January to Congress, which predated the northern Mali takeover but judged that the group “was prioritizing local interests . . . over transnational operations.”

J. Peter Pham, of the Atlantic Council’s Ansari Africa Center, said that “taken in isolation,” Clinton’s remark “would seem to be a slight bit of hyperbole.”

But with its links to other extremist groups, terrorist strikes outside of Mali, and involvement in drug trafficking to Europe, AQIM poses a threat beyond the Sahel as far as Western Europe, Pham said.

He characterized the group as “a threat to international security.”