At first glance, the latest incident of oilfield hostage-taking by South Sudan insurgents appears unremarkable — the same old story of innocent oil workers falling victim to border insecurity, usually freed later but sometimes paying for political and diplomatic gridlock with their lives.

Kidnapping for ransom has become commonplace in South Sudan — of United Nations contractors, aid workers and even refugees — with fingers pointing not only at fractured rebel groups but also the government’s own paranoid security services.

Fighters loyal to former vice president Riek Machar claimed last weekend to have seized four engineers from India and Pakistan contracted to Dar Petroleum, ostensibly in a bid to frighten foreign companies away from the Melut basin’s Adar Yale fields. This was the second group to be abducted this month.

Output from Unity and Upper Nile States has fallen below 130,000 barrels per day, but the Sudan People’s Liberation Movement (SPLM) government aims this year to double production — with stakeholders including the Chinese Petroleum Corporation, Sinopec, ONGC Videsh, Petronas and Tri-Ocean Energy charged with rehabilitation.

Armed conflict with the Muslim North may be in abeyance but the Dinka-dominated SPLM has its hands full fighting off increasingly splintered home-grown rebels, with mediation having all but broken down between President Salva Kiir and Machar, a Nuer militia leader now exiled in South Africa.

Hostages have been killed before, most infamously in 2008 with the death just across the border in Southern Kordofan of five Chinese workers kidnapped from an oilfield in the disputed Abyei district by the Darfuri rebel Justice & Equality Movement (JEM).

JEM denied responsibility and similar threats did eventually recede with implementation of the 2005 Comprehensive Peace Accord, but a decade later the strategy has resurfaced — this time in the South, now a failing state wracked by genocide and famine.

Tribal disaffection within the SPLM has triggered high-profile defections from the army —the last hope for nurturing national unity in this, the world’s newest independent state.

Gone is Brigadier General Henry Nyago, director of military justice, gone is military courts boss Colonel Khaled Loki, gone is veteran SPLM Labour Minister Gabriel Lam and now General Thomas Cirillo Swaka — Kiir’s powerful Chief of General Staff & Logistics — all within a month.

Swaka, an ethnic Bari from the capital Juba, owes allegiance to no faction but has galvanised support among diverse tribes and militias, calling for “the birth of citizen-imposed change” and pledging his newly formed National Salvation Front to overthrow Kiir and restore law and order.

But if oil is the prize, why would anyone kill the goose that lays the golden egg?

Perhaps the answer lies in Kiir’s weakening grip on power and the need for rebels to cut the flow of blood to his flagging command — the kidnappers say they will target oil production to stop Juba buying guns to fight them.

After 12 years in power, Kiir seems unwilling to give way and may only be dislodged by a fresh military offensive that starves him of ready cash — and with Machar’s star waning it seems Swaka could be set to lead a unified resistance.

Swaka has shown grit and has garnered support from western players exasperated with Kiir’s erratic style — earlier this year the UK, US and Norway were forced to deny charges levelled by the SPLM of plotting to kill Kiir’s ailing eminence grise and chief of staff, Paul Malong.

For good or ill, change is coming in South Sudan.

Weekly

Change on radar for South Sudan