SOUTH SUDAN OPPOSITION FORCES CALL FOR MARCH ON JUBA AFTER BATTLEFIELD GAINS . (PHOTO).

 South Sudan opposition forces call for march on Juba after battlefield gains 

South Sudan's main opposition faction called on its forces on Monday to advance on the capital Juba after they captured a strategic town last week.

It was not clear whether the Sudan People's Liberation Army-in-Opposition (SPLA-IO), which battled forces loyal to President Salva Kiir during a 2013-18 civil war, could credibly threaten Juba.

But the call signalled an escalation in the SPLA-IO's rhetoric and ambitions following months of intense clashes around the country that the United Nations has said are occurring at a scale not seen since 2017.

The SPLA-IO seized the town of Pajut, which is more than 300 km (180 miles) north of the capital, in heavy fighting last week in the north of Jonglei State. Pajut's capture puts the state capital of Bor within striking distance of the SPLA-IO.

Deputy Chief of Staff for Operations Wisley Welebe Samson ordered SPLA-IO forces "to move to Juba from all directions of South Sudan and remove the anti-peace regime in Juba", SPLA-IO spokesperson Col. Lam Paul Gabriel said in a statement, Reuters reported.

Kiir's forces battled those loyal to his vice president, Riek Machar, in the 2013-18 war, which was fought along largely ethnic lines and cost about 400,000 lives. A peace deal in 2018 quieted the conflict, although localised clashes persisted.

Heavy fighting surged again last year after an ethnic militia with historic ties to the SPLA-IO overran an army base in the northeastern town of Nasir.

The government then arrested Machar, who had returned to the vice presidency under the peace deal, and charged him with treason and crimes against humanity for his alleged role in the incident.

Machar has denied the charges during an ongoing trial.

Bol Deng Bol, a civil society activist in Jonglei, said the fighting since last week had caused many people to flee their homes, many into uninhabitable swamps.

The U.N. Commission for Human Rights in South Sudan condemned the "deliberate sabotage" of the 2018 peace agreement, including what it said were indiscriminate aerial bombardments.