The separatist revolt in Yemen's south which began four weeks ago appeared close to defeat on Wednesday after forces supporting the internationally-recognised government entered Aden. Approaching from the north-east, the government forces are reported to have taken the airport (see map) and the presidential palace. Fighting continues, though, raising the spectre of a bloody battle for the city.
This morning on Twitter both sides are claiming victory – and at least one of them must be wrong. There's also talk from the separatists of sending in reinforcements and according to unconfirmed reports Emirati warplanes have been attacking government forces. Hard information is scarce and the overall picture is still very muddled (I'll add updates if the situation becomes clearer during the course of the day.)
In theory the government and southern forces are allies in the Saudi-led coalition fighting the Houthis who control much of northern Yemen, but they have political differences. The southern forces are trained and supported by Saudi Arabia's main coalition partner, the UAE, but they are also linked to a separatist movement which seeks independence for the south.
Government and southern forces have clashed periodically before but the current conflict is the most serious since the war with the Houthis began four years ago.
Tensions came to a head after two separate attacks killed dozens in Aden on 1 August. A missile strike by the Houthis hit a military ceremony involving southern forces, killing Abu al-Yamamah, a prominent separatist commander, along with many others. Earlier in the day a suicide attack attributed to Islamist militants hit a police station.
Separatists accused the government of failing to provide adequate protection and on 10 August, following several days of clashes, they took control of Aden. From there, they extended their influence to other parts of the south, making relatively easy gains until they met fierce resistance in Ataq, in Shabwa province (more background here).
Ataq is the gateway to an oil-producing region further north which is claimed by the separatists but held by government forces. Following a battle in and around Ataq on 22 August, separatist forces throughout Shabwa capitulated rapidly, forfeiting their earlier gains in the province.
On Wednesday morning government forces continued their advance, moving rapidly through the neighbouring Abyan province – apparently with little resistance – to reach Aden.
The question now is whether there will be a fight to the finish over Aden or some kind of deal. Despite separatist talk of resistance, the most likely outcome is a temporary fix to avoid tearing the Saudi-led coalition apart.
In any case, from the coalition's point of view, the southern issue is an unwelcome distraction and striking a deal to end it quickly would allow them to focus once again on the main battle – which is against the Houthis.
A prolonged or heavy-handed military campaign against the separatists, far from crushing their movement, would also risk stirring up further local resentment and causing worse problems in the future.
Internationally, the separatists have no significant support except from the UAE. This dependence gives the Emiratis power to rein them in as and when it chooses, but not to control them totally. The separatists, in turn, point out that the coalition needs their services.
The coalition's reliance on southern forces was highlighted yesterday by claims that the Amaliqa ("Giants") brigade, which has been opposing the Houthis near Hodeidah, is moving south to help defend Aden against the government. This may just be posturing but it shows that despite their recent losses the separatists still hold some cards.
For the Emiratis, if not the Saudis, the troublesome separatists are also seen as politically useful because of their opposition to Islamist influence in the "legitimate" government.
Even if negotiations do bring the fighting to a halt during the next few days the underlying issues of southern separatism and tensions in the Saudi-Emirati relationship can be expected to continue bubbling below the surface – until the next flare-up.