( CNN ) -- The president of Sudan declared a state of emergency Sunday for cities along the hotly contested border with South Sudan , where Sudanese fighter jets launched at least one attack against their neighbor 's ground forces . Sudanese President Omar al-Bashir said the state of emergency covers cities in the provinces of South Kordofan , White Nile , and Sinnar , which are on the eastern half of its border with South Sudan . A journalist in South Sudan 's Unity state , just over the border from South Kordofan , reported coming under attack by Sudanese helicopter gunships and MiG fighter jets Sunday morning . Robyn Kriel said she was traveling to the front line with the Sudan People 's Liberation Army of South Sudan when they came under heavy fire for 15 minutes . They all took cover in trenches dug by the army , she told CNN . The SPLA was poorly equipped for the fight , she reported . Soldiers used anti-aircraft missiles and even hand-held weapons that they fired in the air , she said . At least four SPLA soldiers were hurt in the attack , she said . The South Sudanese military reported another attack on Unity state Saturday , though a Sudanese military spokesman denied it was involved . South Sudan split from Sudan last year as part of a 2005 peace deal that ended decades of war in Africa 's largest nation . The war left 2 million people dead and ended with the peace agreement that included an independence referendum for the south . Significant issues between the countries remain unresolved , however , including status of their citizens , division of national debt , disputed border areas and sharing of oil wealth . Tensions peaked this month when South Sudan seized the oil-producing region of Heglig , a resource that fuels the economies of both nations , from its northern neighbor . Heglig oil facilities account for about half of Sudan 's production of 115,000 barrels a day . South Sudanese forces withdrew days later after Sudan lodged protests with the United Nations and African Union , but South Sudan said it continued to come under aerial and ground attack .
A journalist in South Sudan says Sudanese forces attacked them Sunday . She was interviewing South Sudan soldiers near the border . Tensions peaked this month after South Sudan seized the Heglig oil fields .