Officials in Southern Sudan say a fuel blockade by the northern government has sent fuel prices skyrocketing and prompted fist fights at gas stations.
The mayor of Juba accuses the Khartoum government of attempting to destabilize the south ahead of its July independence. The oil-rich south does not have its own refineries and all pipelines run through the north.
The north denies the allegation. But a top U.N. official says the Sudanese government began enforcing a blockade of main oil routes in early May.
The south voted overwhelmingly in January to secede from the north, but tensions have recently spiked over a disputed border region.
Recent clashes have threatened to unravel the 2005 peace deal that ended more than two decades of civil war that left at least 2 million dead.