The military wing of South Sudan's opposition said Wednesday that two training bases on the outskirts of the capital Juba had been attacked by forces allied to the president, stoking fears of renewed conflict.
The attacks are the latest in a series of clashes in Africa's youngest nation, where fighting between forces allied to President Salva Kiir and First Vice President Riek Machar threaten a fragile 2018 power-sharing agreement.
The peace deal ended a five-year civil war that killed around 400,000 people, but South Sudan -- which declared independence in 2011 -- has remained plagued by instability and insecurity.
The Sudan People's Liberation Army In Opposition (SPLA-IO) said "the South Sudan People's Defence Forces attacked Rambur training centre" on Monday afternoon, northwest of Juba.
Another "violent act" occurred at around 4:00 am (0300 GMT) on Wednesday, when the SSPDF launched an assault on Rajaf training centre, SPLA-IO spokesman Lam Paul Gabriel said on Facebook.
Two AFP correspondents in Juba said they heard detonations in the early hours of Wednesday morning.
The training centres were established to prepare opposition forces for integration into the unified army, a key provision of the 2018 peace agreement aimed at uniting federal and opposition troops.
The military has not confirmed the incidents.
However, Gabriel condemned the attacks as an act of "terrorism", calling on the international community to intervene.
"The SPLA-IO reserves the right to defend itself against any attack against its positions," he added.
It comes a day after the opposition condemned an attack on one of its army bases, describing it as a "provocative action" that violated the 2018 deal. The SSPDF did not confirm the strike.
Army spokesperson Lul Ruai Koang warned earlier in the week that Machar's forces were "scaling up their movements" near the capital and had sent out a patrol towards army positions "clearly in military formation".
The incidents follow weeks of clashes in the northeast between federal forces loyal to the president and the "White Army" militia, which the government accuses of collaborating with Machar.
The tensions have provoked concerns from international observers, with the United Nations warning that South Sudan was "teetering on the edge of a relapse into civil war".