Sudan and South Sudan are accusing each other of launching new attacks.<br/> <br />The South says four of its soldiers were killed in an attack by Sudan's armed forces ten kilometres on its side of the border.<br/> <br />Sudan denies the allegation and says it repelled an assault on its own side of the border by rebels it accuses the South of controlling.<br/> <br />The development appears to dash international hopes that tensions could be calmed by the South's agreement to withdraw from a town it's seized in a disputed oil-rich area.<br/> <br />South Sudan says this oil field in Unity was bombed by the Sudanese air force last week.<br/> <br />SOUNDBITE: SOUTH SUDAN ARMY OFFICER, CAPTAIN KUER JUACH ATEM, SAYING (English):<br/> <br />"They want to destroy this oil refinery because they don't have any resources, because this oil belongs to the South."<br/> <br />So far both sides have failed to heed international pressure to return to the negotiating table.<br/> <br />U.S. President Barack Obama is urging both sides to resume talks over a series of territorial and oil-related disputes between them.<br/> <br />Any return to widespread fighting would be devastating for both neighbours, harming their oil-dependent economies and forcing refugees and fighters into the surrounding region.<br/> <br />South Sudan only became an independent state last year after decades of civil war with Sudan that killed about two million people.<br/> <br />Paul Chapman, Reuters
