Dusk, and from the churchyard of Saint Alphonse came the plangent harmonies of one of the best known choral works of the Catholic church.

Under the lime trees, 30 men and women practised the 17th-century setting of Psalm 51 by Gregorio Allegri, accompanied by a recorder, a battered violin and distant sounds of traffic.

A few days before and the streets of Matete district, Kinshasa, had seen running battles between youths protesting the expiration of President Joseph Kabila’s mandate, and security forces. More than 40 people had died across the city.

Now the sounds of conflict had gone away. The choir’s Latin rose in volume. “Miserere mei, Deus,” they sang. “Have mercy upon me, O God.”

There has been little Christmas spirit in the Democratic Republic of Congo (DRC) in recent weeks, and many appeals for divine clemency.

Officials and opposition politicians are locked in talks to defuse a potentially explosive situation. The government says that Kabila, president of the vast resource-rich central African state since 2001, has no desire to remain in power indefinitely.

Policemen sit on a monument at the central station, Kinshasa. Photograph: Robert Carrubba/Reuters

Elections have simply been postponed so the huge logistic and financial obstacles to holding polls can be overcome, perhaps in 2018, says Barnabé Kikaya, a presidential adviser.

However, the opposition has little confidence in such promises and, though the talks now look close to a deal, nothing has been signed.

“It’s a power struggle, whether around a table or in the street,” said Valentin Mubake, a senior official of the UDPS, the main opposition party.

Kabila now appears to have won the first round of hostilities that followed the end of his second five-year term last week: he is constitutionally banned from seeking a third.

The authorities deployed tens of thousands of police and soldiers, with armoured vehicles guarding strategic points, and cut off social media. Snatch squads went house to house during the night, picking up agitators. Protesters blew whistles and waved red cards, but any gathering was rapidly broken up.

“The bullets were flying just outside. It’s still very tense. But what can you expect? The people are angry. Even the graduates don’t have jobs. Prices are rising all the time. People are hungry,” said Modibo Jamali, 56-year-old director of a school for disabled children in Matete.

Others complain of entrenched corruption at all levels, and predatory police. The Guardian’s car was stopped in central Kinshasa by drunk, armed officers who stole money saved by the driver over months to pay for his three-year-old’s back operation.

Despite the groundswell of popular anger, Kabila’s grip on power remains strong. The security forces remain broadly loyal, and many ordinary people see the current opposition as part of the problem, not the solution.

“They are all robbers, looking out for themselves,” said a chef in one five-star hotel favoured by politicians and their relatives, where a cocktail costs $20 (£16) and the restaurant offers a $150 New Year’s banquet.

Anti-Kabila demonstrators and UN peacekeepers last week. Photograph: Thomas Mukoya/Reuters

Observers say the rigid position of Étienne Tshisekedi, the 84-year-old leader of the UDPS, has helped marginalise his party. The most popular opposition politician, Moise Katumbi, a tycoon who owns a successful football club, fled DRC after receiving a jail sentence for minor charges of fraud – which supporters say are trumped up.

Katumbi is still overseas, where his efforts to rally western support have had some success, but he said last week that he was not planning on returning soon, for fear of prompting violence. “I am a man of peace,” he told the Guardian.

One result of the ongoing crisis is a wave of nostalgia among older generations for the era of Mobutu Sese Seko, who ruled DRC, which he named Zaire, from 1965 to 1997.

Mobutu, who was supported by the west during the cold war, was a brutal dictator who left a legacy of economic ruin and civil war, which lasted five years and killed an estimated 5 million people.

This is not what many remember, or choose now to recall.

“These days, Congolese people regret the passing of Mobutu because he unified the country, and he gave people dignity,” said Kambayi Bwatshia, a historian and analyst who served Mobutu briefly as a minister.

“He made Zaire known all over the world. Heads of state came here, the pope, too, the Congolese football team qualified for the World Cup. Since then, we have been in continual crisis and you can’t help but say: if Mobutu had been here …” Bwatshia said.

The best known event was the Rumble in the Jungle: the world heavyweight boxing title bout in Kinshasa, in which Muhammad Ali beat George Foreman in 1974, which was hosted and paid for by Mobutu.

The fight took place in what is now the Tata-Raphaël stadium. On one side of its dilapidated concrete terraces is a new private football coaching school, offering lessons to those children whose parents can pay $40 each month. On the other side is a row of cheap bars and cafés, where beer costs a dollar for a litre bottle and former sportsmen remember better times.

Men exercise at Tata-Raphaël stadium in Kinshasa. Photograph: Eduardo Soteras/AFP/Getty Images

“Back in those days, the 70s and 80s, we had foreign coaches coming here. Imagine! Now all the good players go to Europe,” said Baby Nsimba, a former international footballer.

Yards away, Mami Alangi, who sells omelettes to patrons of the bars, smiled as she remembered Mobutu’s helicopter landing on wasteland nearby for annual rallies in the stadium.

“They were good times. There were hospitals, schools that you could afford. Now, if I make enough to feed my family during the day, I’m happy,” Alangi, 41, said.

Analysts suggest three possible outcomes of the current crisis: that the instability is “transitional” and leads to process, which brings any new government domestic and international legitimacy; a massive and bloody, popular urban uprising to oust the president; or the slow collapse of the government as economic weakness, meddling by regional powers and international isolation undermine its authority. In this final scenario, rebellions in the restive east would play a key role in “hollowing out” the government. Militias there killed at least 34 civilians over the weekend.

“No ruler has fallen because of what happens in Kinshasa. Their resources are drained by the sheer effort of controlling the country, and then they topple,” said one Kinshasa-based western expert.

The district of Ngaliema is the other side of the capital from the stadium and the church of St Alphonse. The road across the city runs through Ngombe, the wealthy central area, then alongside the powerful narrow stream of the Congo river itself, muddy brown under the slate grey sky.

Ngaliema is on a hill, near the base of the feared Republican Guard, Kabila’s praetorians. On the barracks wall is a badly painted picture of Laurent Kabila, the current president’s father, and ruler from 1997 until his assassination in 2001. It shows the guerrilla commander raising an admonitory finger above the words: “Never betray the Congo”.

The local member of parliament in Ngaliema is the firebrand opposition leader Franck Diongo, who was arrested during the protests after a confused fracas with some Republican Guards. Hours after Diongo’s detention, the neighbourhood was tense. Soldiers and policemen milled about the muddy lanes. A nervous patrol of United Nations peacekeepers sweated in an armoured truck. Crowds of angry teenagers gathered down narrow alleys flanked by low brick and tin homes.

The complaints came thick and fast. Few of the speakers could remember the civil war, let alone Mobutu.

“We’ve had enough,” Sylvain, 19. “Things have to change. I don’t know how, or when. But it all has to change.”