Mozambique's largely deserted capital was hit on Tuesday by skirmishes between protesters and police, AFP reporters said, the day after the ruling party was controversially confirmed winners in recent elections.
Police in armoured vehicles patrolled the centre of the city, where hundreds of protesters in small, scattered groups threw objects and started fires.
Makeshift roadblocks on major thoroughfares were set alight on Monday evening, covering the city with thick smoke, soon after the country's highest court confirmed the victory of the ruling Frelimo party presidential candidate Daniel Chapo.
At least 21 people, including two police officers, have been killed in Mozambique in the last 24 hours, the government said.
A total of "236 acts of serious violence were reported" across the country, leaving at least 25 people wounded including 13 police officers, Interior Minister Pascoal Ronda told a press conference late Tuesday.
"Groups of armed men using bladed weapons and firearms have carried out attacks against police stations, penitentiary establishments, and other infrastructure," Ronda said.
More than 70 people have been arrested, he added.
Chapo's main challenger, exiled opposition leader Venancio Mondlane, has claimed the election was rigged, sparking fears of violence between rival party supporters.
Shops, banks, supermarkets, petrol stations and public buildings meanwhile were ransacked, with their windows smashed and contents looted. Some were set on fire and reduced to smouldering rubble.
"Maputo Central Hospital is operating in critical conditions, more than 200 employees have not been able to reach the site," its director Mouzinho Saide told AFP, adding that nearly 90 people had been admitted with injuries.
Forty were injured by firearms and four by knives, he added.
Main roads leading to Maputo and the neighbouring city of Matola were blocked by barricades and burning tyres, while the road leading to Maputo airport was largely impassable.
Most local residents stayed at home, with the few who ventured out doing to look at the damage or do last-minute Christmas shopping.
Christmas Eve is normally a busy time, with large crowds in central Maputo but shops and even small neighbourhood grocery stores were closed, making petrol and bread unavailable.
Public transport was also paralysed, with only ambulances and funeral vehicles running.
'Humiliation'
The unrest spread to several cities in the northern part of Mozambique, local media reported, with violence and vandalism in the provinces of Cabo Delgado, Nampula, Zambezia and Tete, where opposition support is strong.
More than 100 people have already died in the unprecedented post-election violence, with fears that the toll could increase after Mondlane's claim of victory.
Mozambicans are demanding "electoral truth", he said in a Facebook post. "We must continue the fight, remain united and strong."
Monday's confirmation of the result of the October 9 election came despite claims of irregularities from many observers.
Chapo won 65.17 percent of the vote, more than five points lower than the initial results declared by the country's electoral commission.
In the National Assembly, Frelimo has a majority of 171 seats out of 250, down 24 from the announcement in October.
"Venancio", as Mondlane is called on the street, repeated his assertion in a social media message on Tuesday that the constitutional court was "legalising fraud" and "the humiliation of the people".
"We want to create a People's Constitutional Court, which will confirm Venancio Mondlane as president," he said of himself.
"I will be sworn in and invested," he added.
Chapo, who is due to take office in mid-January, struck a conciliatory tone in his victory speech on Monday, promising to "talk to everyone", including his main opponent.
(FRANCE 24 with AFP)