A Southern Sudanese government minister was shot dead by his personal driver on Wednesday, an army spokesman said.

The driver then killed himself, said Col. Philip Aguer.

The cause of the shooting was not immediately clear but appears unrelated to Southern Sudan's successful independence referendum from the north.

Jimmy Lemi Milla, the minister of cooperatives and rural development, and his driver are believed to be related by marriage, said Aguer.

The final results of Southern Sudan's independence referendum held last month were announced Monday. Nearly 99 percent of southerners voted for secession. The oil-rich south is expected to become the world's newest nation July 9.