Sudanese armed forces have reportedly launched an attack more than six miles inside South Sudan's border, days after the south announced it was pulling its troops from a disputed border town to avoid an all-out war between the two countries.
Ground troops from Sudan launched three waves of attacks, said Major General Mac Paul, deputy director of military intelligence for South Sudan.
A soldier's body and two wounded soldiers were brought to a hospital, said Dr Zecharia Deng Aleer, clinical director at the Rubkona Military hospital.
Dr Aleer said the soldiers were brought in from around the Pariang Junction in South Sudan's Unity State.
Maj Gen Paul said it was the first major engagement between the two armies since South Sudan announced it would pull out from the contested border town of Heglig. He said the Sudanese forces "have come deeply in the south" and attacked with artillery and tanks. He said the attack was part of a "continuous provocation from the Sudanese Army".
Sudan's military spokesman and other government officials were not immediately available to comment on the attack.
Sunday's military attack came hours after a Muslim mob burnt a Catholic Church in Sudan frequented mostly by South Sudanese.
The church in Khartoum's Al-Jiraif district was built on a disputed plot of land, but the Saturday night incident appeared to be part of the fallout from ongoing hostilities between Sudan and South Sudan over Heglig.
Witnesses and several newspapers said a mob of several hundred shouting insults at southerners torched the church. Fire engines could not put out the fire, they said.
Sudan and South Sudan have been drawing closer to a full-scale war in recent months over the unresolved issues of sharing oil revenues and the disputed border. Talks between the two countries over the unresolved disputes, which were being mediated by the African Union, broke down in Ethiopia earlier this month.