South Sudan's leader accused Sudan of declaring war on Tuesday as Khartoum's fighter jets bombed border regions in defiance of international calls for restraint.
Several people were wounded in a multiple air strikes on the villages in the South's oil-rich border regions overnight, reaching around 25 km from the frontline between the rival armies.
Salva Kiir, on a visit to Beijing where he met President Hu Jintao, said his “neighbour in Khartoum has declared war on the Republic of South Sudan”.
Last week, Sudan's President Omar al-Bashir threatened to crush the “insect” government of the South, and said the time for talks was over.
Beijing — a key ally of Khartoum but also the main buyer of the South's oil — has repeatedly called for an end to weeks of border fighting, which saw the South seize and hold the key Heglig oil field from Sudanese troops for 10 days.
Despite the South's withdrawal from Heglig at the weekend, both armies are reportedly reinforcing troop numbers and digging into trenches along their contested border.
Overnight Monday, bomber aircraft hit border villages in the South's Unity state following earlier air strikes on the state capital Bentiu, governor Taban Deng said.
“There are wounded people who have been evacuated to Bentiu hospital, some of them are farmers, some are soldiers,” said Mr. Deng.
Khartoum has repeatedly denied it has launched air strikes on the South, but United Nations chief Ban Ki-moon on Monday deplored the cross-border air raids, and called on both nations to prevent the fighting escalating further.
Border tensions are high, although Mr. Deng said at present “with the exception of aerial bombardment, the front line is quiet”.
South Sudan has warned it will fight back if Sudan does not end its aerial attacks. “We cannot be sitting at the mercy of the Sudanese air force,” Mr. Deng added.
