South Sudan's First Vice President Riek Machar has been charged with murder, treason and crimes against humanity.

The vice president's indictment has sparked fears that the country could spiral into civil war.

The case against the country's Justice Minister, Joseph Geng Akech, is based on an attack on him in March last year.

The main road to his residence in the capital, Juba, has been blocked by tanks and soldiers.

Forces loyal to Machar fought for five years with rebels supporting President Salva Kiir, ending the conflict with a peace deal in 2018.

Machar has been under house arrest since March last year and has been calling for calm from the United Nations, the African Union, and neighboring countries.

Although the civil war, which has claimed 400,000 lives, ended under a peace deal signed in 2018, relations between Machar and Kiir have become increasingly strained, leading to tensions and occasional clashes between the two nations.

Seven other people have been charged along with Machar, including Oil Minister Phut Kang Chol and Deputy Minister of the Army Lt. Gen. Gabriel Duop La, Justice Minister Joseph Geng Akech said in a statement.