Sudan President Omar al-Bashir has warned that Southern Sudan would struggle as an independent nation if its people vote to secede in a forthcoming referendum.
He told al-Jazeera TV the south did not have the ability to create a stable state or provide for its citizens.
The comments will infuriate the SPLM - ex-rebels who have ruled the south since civil war ended in 2005 reports the BBC.
The South's widely expected to choose secession from the predominantly Muslim north.
The ruling party in the South says a vote for independence will complete their so-called walk to freedom.
US Consul General to the South, Barrie Walkey, said thousands of southerners living in the North of Sudan had already moved back South ahead of the referendum, because they're unsure what might happen if they stay behind.