Sudan and South Sudan agreed Monday during a visit to Juba by President Omar al-Bashir to consider setting up a joint force to protect vital oilfields.

Sudan and South Sudan agreed Monday during a visit to Juba by President Omar al-Bashir to consider setting up a joint force to protect vital oilfields, his foreign minister said.

"Sudan and South Sudan are in consultations about the deployment of a mixed force to protect the oilfields in the South," Ali Ahmed Karti said, adding that Juba had come up with the proposal.

Bashir visited Juba as South Sudan's government and opposition were starting formal peace talks in Addis Ababa aimed at ending more than three weeks of unrest.

South Sudan won independence from Khartoum in 2011 after decades of war, but the north remains a key player -- serving as the export route for the South's oil.

On Sunday, the South's army spokesman Philip Aguer said government forces were on the offensive in the oil-producing Unity and Upper Nile states in the north of the country.

Despite its oil wealth, accounting for about 80 percent of 2012 gross domestic product, South Sudan is one of the continent's least developed countries.