South Sudan has blamed its northern neighbour, the Republic of Sudan, for the aerial

bombardment

of a refugee camp south of the border. Residents of the camp in Unity state said a plane circled overhead before dropping five bombs. Sudan's army has denied it's responsible for the attack. James Copnall reports from the refugee camp.

The camp hosts refugees from the war in Southern Kordofan over the border in Sudan. There, northern rebels, who once fought on the side of the South Sudanese, are fighting the Sudanese government again. The governor of Unity state, Taban Deng,

put the blame firmly on

Sudan. He said President Omar al-Bashir should be asked hard questions about the bombing, incidents like this. Both sides' belief that the other is sponsoring rebels on their territory are making an already

shaky

relationship worse.

Partial results released by Liberia's National Election Commission show the incumbent President Ellen Johnson Sirleaf is leading with just over 90% of the vote. Turnout was as low as 33% partly due to a boycott by the opposition candidate Winston Tubman, who alleged fraud in the first round. International observers rejected his allegations.

One of President Obama's most influential advisers on the Middle East, Dennis Ross, has announced that he's

stepping down

. Mr Ross, who's 62, said he took the decision for personal reasons. He joined the Obama administration in 2009. Another American Middle East envoy George Mitchell stood down in May. Correspondents say White House expertise on the region is now much diminished.