Southern Sudanese citizens chant slogans and hold placards as they march in the streets in support of the independence referendum in Juba
Photograph by: STR
The disclosure comes at a time when tensions between north and Southern Sudan are growing ahead of a referendum on independence for the south.
The controversy began in September 2008 when pirates hijacked a Ukrainian-owned freighter, the MV Faina, off the coast of Somalia as it headed for the Kenyan port of Mombasa.
While still under pirate control, the Ukrainian government confirmed that there were 33 T-72 tanks and other military equipment on board.
A highly embarrassing situation quickly developed for Kenya, which helped broker the 2005 peace deal that ended a 21-year civil war between the mainly Muslim north Sudan and the Christian and Animist south.
Both Ukraine and Kenya insisted the weapons were destined for use by the Kenyan army - a claim made to look unfeasible when media got their hands on the manifest, which seemed to indicate the final recipient was the government of Southern Sudan.
The denials continued unabated, but a cable from the United States embassy in Nairobi from October 2008 described it as "a poorly-kept secret, however, that the shipment was originally bound for South Sudan."
According to the leaked cables, the US State Department took the arms transfers seriously when they happened, as they involved a breach of an arms embargo.
The US Ambassador to Kenya, Michael Ranneberger, threatened Kenya in December 2009 with "sweeping sanctions" if they transferred the 33 tanks and ammunition to Southern Sudan, according to the WikiLeaks cables.
However, this position "confused" the Kenyan government. The US was aware of previous, secret shipments under George W Bush, according to a Kenyan official quoted in the cables, but was strongly opposed to the latest delivery of tanks under President Barack Obama.
The MV Faina was released after five months when a 3.2-million- dollar ransom was paid. The tanks, which were delivered to Mombasa and would have been transported to Southern Sudan overland were it not for the pirate attack, are reportedly still in the East African nation.
The timing of the revelation is potentially damaging as Southern Sudanese are scheduled to vote on their independence on January 9.
Preparations for the historic vote have laid bare the deep distrust that remains between the two sides. US Secretary of State Hillary Clinton has called the situation a "ticking time bomb," and both sides are believed to have a large arsenal of weaponry at their disposal.
Three reported incidents of northern army attacks near the north-south border in Greater Bahr el-Ghazal have increased concerns of a return to war.
The northern government has accused the south of voter intimidation and a lack of transparency during the recently completed registration for the January referendum.
However, southern army officials downplayed the significance of the revelations.
"That happened two years ago. I have nothing to say about old news," Colonel Philip Aguer, spokesman for the Sudan People's Liberation Army, told the German Press Agency dpa.
Northern officials could not be reached for comment, although an adviser to Sudan's President Omar al-Bashir told the New York Times he was not surprised and that the shipments could become "a very hot political issue."
Reaction in Kenya and Ukraine, where few believed the denials, was muted.
Government denials in Ukraine lost their credibility last year when photographs and reports surfaced showing Made-in-Ukraine military kit with the name of a Southern Sudan addressee stencilled on the kit.