A South Sudanese activist said on Monday that he and four others had gone into hiding, abandoning plans for an anti-government demonstration as the authorities warned of a tough crackdown against any protesters.

The world’s newest nation has suffered from chronic instability since independence in 2011, with deepening discontent prompting civil society groups to urge its leadership to step down, saying they have "had enough”.

The demonstration was set to take place the same day as President Salva Kiir inaugurated a newly-created national parliament, a key condition of a 2018 peace deal that ended the country’s brutal civil war that killed nearly 400,000 people.

But as heavily-armed security forces patrolled the capital Juba, protesters were nowhere to be seen, with one organiser telling AFP that he and four other members of the People’s Coalition for Civil Action (PCCA) were now in hiding and feared for their lives.

"It is a peaceful protest; it is supposed to be non-violent but the government responded with violence,” said Wani Michael.

"There have been massive deployments... these guys are carrying AK-47s, they are carrying machine guns, and there are tanks on the roads. So citizens fear... they will be met with violence,” he added.

The government has taken a hard line against the PCCA calls for a peaceful public uprising, arresting at least eight activists and detaining three journalists this month in connection with the demonstrations, according to rights groups.

Juba residents told AFP they were afraid even to leave home.

"We are hearing that there is no work today, and besides we are fearing [what the day will bring],” food hawker Emelda Susu said.

"I will go to the market when I see things are normal, but for now one’s life [comes] first, my friend. Yes I am fearing so I have to be careful,” said Jimmy Bandu, a small-scale trader.

National security officers with militarised mounted vehicles patrolled usually busy neighbourhoods in Juba, which also saw a ramped-up police presence and low levels of traffic.

Pledge for ‘free, fair’ vote 

The authorities have branded the protest "illegal” and warned of strict measures against anyone who defies the ban.

"The government is in full control and... so everybody should resume his or [her] normal duties and... not fear anything,” Information Minister Michael Makuei told AFP.

He dismissed reports of an Internet shutdown after users reported difficulty accessing two of the country’s main networks, Zain and MTN, blaming any problems on technical troubles.

With the mood in the usually bustling capital decidedly subdued, Kiir told members of the new parliament to "place the people of South Sudan above any narrow party interest”.

"Our final mandate in this [peace] process is to hold free, fair and credible democratic elections at the end of the transitional period,” he added, referring to long-delayed polls now expected in 2023.

In a sign of the lingering challenges facing the country, Kiir also announced that the government was pulling out of negotiations with the South Sudan Opposition Alliance (SSOMA), a coalition of rebel groups.

The talks, which were brokered in Rome by a Catholic association with ties to the Vatican, have failed to curb violence in the south of the country, despite a ceasefire signed in January 2020.

"While the quest for an inclusive peace in our country remains our sole objective, recent killings of innocent civilians... have tested our patience,” Kiir said, accusing rebels from the National Salvation Front — a member of SSOMA — of indiscriminate attacks.

The peace process has suffered from years of drift and bickering following the 2018 ceasefire and power-sharing deal between Kiir and his former foe Vice President Riek Machar.

The PCCA — a broad-based coalition of activists, academics, lawyers and former government officials — has described the current regime as "a bankrupt political system that has become so dangerous and has subjected our people to immense suffering”.