Sudanese warplanes bombed South Sudanese frontline positions four times at the weekend, while militia forces were attacking Southern troops in border areas, the Southern army said Monday.
"There is still bombardment in Panakuach," with four bombs dropped near the South Sudanese forward army base, army spokesman Philip Aguer told AFP, the latest violence in weeks of border fighting.
"There has been fighting in Wedakona, Upper Nile state, with Khartoum supported militias" that was still raging early Monday, he said.
Both sides accuse the other of funding rebel militias in their territory, as part of a proxy war until outstanding issues over contested territory, oil revenues and borders are resolved.
Sudanese bomber planes have launched waves of air strikes on Southern military positions, as well as on towns and villages, in the most serious unrest since the South's independence and which has raised fears of a wider war.
After almost a month of fighting, the African Union last week ordered the two sides cease hostilities within 48 hours, but the violence has continued.
It also ordered Sudan to stop its campaign on aerial bombardment, a charge it has repeatedly denied.
On Friday, Juba said another group of Sudan-backed rebels attacked the outskirts of Malakal, capital of the South's oil rich Upper Nile state.
South Sudan seceded peacefully from Sudan in July after 50 years of intermittent civil war. Some two million people died in the last round, between 1983 and 2005.
On Sunday, Sudanese President Omar al-Bashir issued a resolution declaring a state of emergency in the border states of South Kordofan, White Nile and Sennar.