Four senior politicians accused of an alleged coup plot that sparked violence in South Sudan have been freed.

South Sudanese government dropped the treason charges following insistent requests by the rebels to do so.

Justice Minister Paulino Wanawilla said on Thursday that the case was being dismissed to allow peace and reconciliation in the war-torn country.

Pagan Amum, one of the released politicians, told reporters that the withdrawal of the case meant that justice had been denied.

"We were imprisoned without any reason," he said in a speech outside the court. "We have to return South Sudan to peace and stability."

The four men, who have denied the conspiracy accusations, were greeted by cheering supporters, the BBC said.

The charges against them carried the maximum sentence of death.

Their release could represent a turning point for the peace negotiations which have plunged into a stalemate since January, as the government had freed only seven (out of 11) political prisoners accused of a coup.

The conflict in South Sudan started last December when President Salva Kiir, of the ethnic group Dinka, fired former vice-President Riek Machar, an ethnic Nuer, and accused him of plotting to overthrow the regime.

Machar denied the accusation and accused Kiir of carrying out violent purges.

The accusations sparked violence among the two ethnic groups causing the death of thousands and leaving more than a million displaced.

Nearly five months after the conflict started, a report by the UN mission in South Sudan (UNMISS) warned that hundreds of civilians are being killed due to their ethnic origins and nationality.

UNMISS condemned the target killings and the use of radio stations to broadcast hate speech, during which men from one community are called to commit vengeful sexual violence against women from another community.

Several NGOs have pressed the international community to intervene in order to halt the bloodshed.

China and the US have several times expressed their concern over the conflict and have urged the warring sides to reach an agreement as soon as possible.