Businesses have shut in Zimbabwe’s capital, Harare, as the nation awaits the release of heavily disputed presidential election results.
Armed soldiers and police are on patrol, ordering people to “behave”.
Three people were killed in the city on Wednesday in clashes between the security forces and supporters of opposition leader Nelson Chamisa.
He says Monday’s elections were being rigged to give President Emmerson Mnangagwa victory.
The elections were the first since long-time ruler Robert Mugabe was ousted in November.
The polls were intended to set Zimbabwe on a new path following Mr Mugabe’s repressive rule.
However, Mr Chamisa’s MDC Alliance has accused the military of using excessive force to quell Wednesday’s protests.
Mr Mnangagwa said the government was in talks with Mr Chamisa to defuse the crisis and proposed an independent investigation to bring those who were behind the violence to justice.
“This land is home to all of us, and we will sink or swim together,” Mr Mnangagwa said in a series of tweets.
No violence was reported on Thursday. A truckload of armed policemen and soldiers were driving around the city shouting, “Behave yourself, people of Zimbabwe.”
Riot police have also taken positions around the headquarters of the MDC Alliance.
The Zimbabwe Electoral Commission (Zec) has declared Mr Mnangagwa’s Zanu-PF party the winner of the parliamentary election, with a two-thirds majority.
It has not released presidential election results, saying party agents were still verifying the result and there was “absolutely no skulduggery”.
Zec confirmed its website had been hacked, saying it took it down “within 11 minutes” of the attack.
Zanu-PF, which has been in power since the country gained its independence 38 years ago, denies there has been any rigging.
‘Bracing for more trouble’
By Andrew Harding, BBC news, Harare
Shops are closed and shutters are down as the centre of Zimbabwe’s capital braces itself for more trouble.
There is no sign yet of any organised protest by opposition supporters.
President Mnangagwa has blamed the violence on the MDC Alliance and has now promised an independent investigation.
But the issue at the heart of the trouble has yet to be resolved – the outcome of the presidential election which the opposition is convinced is being rigged.
Foreign observers are pressuring the electoral commission to announce the results quickly – and to address concerns about fraud by being transparent about the entire process.
How have foreign powers responded?
UN Secretary General Antonio Guterres urged Zimbabwe’s politicians to exercise restraint, while UK foreign office minister Harriett Baldwin said she was “deeply concerned” by the violence.
The US embassy in Harare advised its citizens to avoid the city centre, following Wednesday’s unrest.
In a message to Zimbabwe’s politicians, it said there was a “historic opportunity to move the country towards a brighter future”.
“Violence cannot be part of that process,” it added.
China, Zimbabwe’s main international ally, said it hoped all sides would put the country’s interests first following a “generally peaceful and orderly” election.
What happened after the vote?
The day after the election, the MDC Alliance said Mr Chamisa had won the presidential election, pre-empting an official announcement and prompting its supporters to celebrate in some areas of Harare
When Zec announced that Zanu-PF had won the parliamentary vote by a landslide on Wednesday, things turned nasty.
The opposition supporters were are also angered by the delay in announcing the presidential results.
Home Affairs Minister Obert Mpofu said the government would not tolerate such protests.
The opposition “are testing our resolve, and I think they are making a big mistake,” he said.
A spokesman for Mr Chamisa condemned the deployment of soldiers and the subsequent loss of life.