The proclamation of an independent "Azawad" by Tuaregs who, with their Islamist allies (or rivals?) have taken northern Mali in the wake of the coup in Bamako (where the coup-makers are now standing down) has raised concerns throughout the Maghreb, but most intensely in Algeria. Seven Algerian diplomats were reportedly kidnapped in Gao, but now have reportedly been released. The kidnappers were supposedly from the Movement for Unity and Jihad in West Africa (MUJWA in its English acronym, MUJAO in its French), an offshoot that broke from Al-Qa‘ida in the Islamic Maghreb (AQIM). Though the diplomats are now said to be free, Algeria is talking tough and saying it cannot accept the breakup of Mali, and there is growing concern that the northern extension of Mali could become a new rogue state aiming at destabilizing the region. Algeria has already had to face raids by AQIM from across its southern border. There were reports even before the kidnappings that Algerian special forces might intervene in Mali (report is in French).
But unsurprisingly, it's kal at The Moor Next Door who has a lot more about the Algerian buildup and the possibility of Algerian intervention. His article, quoting various Algerian reports, seems to suggest that Algeria might intervene in cooperation with the MNLA, the Tuareg force that initially won the north and then found its Islamist rivals pushing it out of the cities. But Algeria is also pledged to the unity of Mali, and cooperation with the MNLA might seem to contradict that goal. Kal's analysis was written before the diplomats' release, so the likelihood of an immediate Algerian intervention may now be much reduced.
There is still considerable confusion about the roles of the Tuareg MNLA, the Islamist Ansar Eddine, and MUJWA in the occupation of the north but they clearly have fallen out among themselves. Al-Jazeera English did score an unusual first with a report on the Ansar Eddine from Timbuktu (and where did they get the tanks?):