BAMAKO, Mali — In life, he delighted in fomenting insurgencies in the African nations to the south. And in death, Col. Muammar el-Qaddafi is doing it all over again.

Hundreds of Tuareg rebels, heavily armed courtesy of Colonel Qaddafi’s extensive arsenal, have stormed towns in Mali’s northern desert in recent weeks, in one of the most significant regional shock waves to emanate directly from the colonel’s fall.

After fighting for Colonel Qaddafi as he struggled to stay in power, the Tuaregs helped themselves to a considerable quantity of sophisticated weaponry before returning to Mali. When they got here, they reinvigorated a longstanding rebellion and blossomed into a major challenge for this impoverished desert nation, an important American ally against the regional Al Qaeda franchise.

The Tuaregs hoisted their rebel flag in the sandy northern towns, shelled military installations, announced the “liberation” of the area and shouted “Allahu akbar,” or “God is great,” according to local officials. Their sudden strength has deeply surprised a Malian Army accustomed to fighting wispy turbaned fighters wielding only Kalashnikov rifles.