PARIS - Some of the culprits in an attack on the U.S. consulate in Benghazi, Libya, had links to al-Qaida's North Africa arm, a top U.S. military official said Wednesday, adding that it remained unclear if the terror network led or organized the deadly assault whose victims included an American ambassador.

Al-Qaida links had been suspected in the attack on Sept. 11, but not publicly detailed, and an investigation is underway. U.S. Ambassador to Libya Chris Stevens and three others were killed. The assault occurred around the same time that protests erupted in Muslim countries over an anti-Islam film made in the United States.

Gen. Carter Ham, the head of the U.S. military's Africa Command, said some of the attackers had ties to Al-Qaida in the Islamic Maghreb, which was built on the remains of a former Algerian militant group.

"Clearly some of these individuals have some linkages to AQIM," Ham told reporters in Paris. "That's not to say that this was an AQIM-planned or organized or led activity." He did not elaborate.

AQIM and its allies control a vast swath of neighboring Mali. The United States and France are among the Western powers that are worried about the Sahel region of northeastern Mali could become a terrorist haven, and are pushing for international action in the region.

"I don't think today they possess a credible, imminent threat to the U.S. homeland. But that network already killed four Americans," Ham said of AQIM. "If we collectively — the international community — do not find a way to help the Africans address this threat, it's going to worsen, the network will become stronger, and they will gain the capability to export violence."

There has been controversy over the U.S. response to the consulate attack, and the Pentagon and the State Department are assessing what additional or improved arrangements might be necessary to secure U.S. diplomatic outposts in the Middle East.