Residents across Southern Sudan are in a jubilant mood after what appears to be a landslide vote to secede from the north and to create the world's newest country.

There's one side effect of this month's weeklong referendum, though, that people are not cheering: higher prices.

Merchants and customers are complaining of price hikes over the last several weeks as the prices of some basic goods like sugar, soap and cooking oil have increased by more than 50 percent.

One factor is that hundreds of thousands of southerners who lived in the north are streaming back south, putting pressure on supplies.

The World Food Program expects prices to continue to rise, a situation that could lead to the need for more food aid.