Zimbabwe’s military has read out a statement after taking over the national broadcaster, ZBC, saying it has taken action to “target criminals”.
However, it said this was not “a military takeover of government” and President Robert Mugabe was safe.
Heavy gunfire and artillery were heard in northern suburbs of the capital, Harare, early on Wednesday.
Zimbabwe’s envoy to South Africa, Isaac Moyo, earlier dismissed talk of a coup, saying the government was “intact”.
The statement read out by Maj Gen Sibusiso Moyo came hours after soldiers overran the headquarters of ZBC. He said: “We wish to assure the nation that his excellency the president… and his family are safe and sound and their security is guaranteed.”
The statement added: “We are only targeting criminals around him who are committing crimes… that are causing social and economic suffering in the country. As soon as we have accomplished our mission, we expect that the situation will return to normalcy.”
The statement did not name those targeted but a government source quoted by Reuters said Finance Minister Ignatius Chombo was among those detained.
It is not clear who is leading the military action.
The UK Foreign Office advised Britons “currently in Harare to remain safely at home or in their accommodation until the situation becomes clearer”.
The US embassy in Harare tweeted that it would be closed on Wednesday “due to ongoing uncertainty”.
It also advised US citizens in Zimbabwe to “shelter in place” until further notice.
The latest events came hours after Zimbabwe’s ruling party accused the country’s army chief of “treasonable conduct” after he warned of possible military intervention.
General Constantino Chiwenga had challenged 93-year-old President Mugabe after he sacked the vice-president.
Below is the full statement
“Good morning Zimbabwe.
Fellow Zimbabweans. Following the address we made on 13 November 2017, which we believe our main broadcaster Zimbabwe Broadcasting Corporation and the Herald were directed not to publicise, the situation in our country has moved to another level.
Firstly we wish to assure our nation, His Excellency, the president of the republic of Zimbabwe and commander in chief of the Zimbabwe Defence Forces, comrade R G Mugabe and his family, are safe and sound and their security is guaranteed.
We are only targeting criminals around him who are committing crimes that are causing social and economic suffering in the country in order to bring them to justice.
As soon as we have accomplished our mission we expect that the situation will return to normalcy.
To the civil servants, as you are aware there is a plan by the same individuals to influence the current purging which is taking place in the political sphere. To the civil service, we are against that act of injustice and we intend to protect every one of you against that.
To the judiciary, the measures underway are intended to ensure that as an independent arm of the state you are able to exercise your independent authority without fear of being obstructed as has been the case with this group of individuals.
To our members of parliament, your legislative role is of paramount importance, of peace and stability in this country, and it is our desire that a dispensation is created that allows you to serve your respective political constituencies according to democratic tenants.
To the generality of the people of Zimbabwe, we urge you to remain calm and limit unnecessary movement. However we encourage those who are employed and those with essential business in the city to continue their normal activities as usual. Our wish is that you will enjoy your rights and freedoms and that we return our country to a dispensation that allows for investment, development and prosperity that we all fought for and for which many of our citizens paid the supreme sacrifice.
To political parties, we urge you to discourage your members from engaging in violent behaviour. To the youth, we call upon you to realise that the future of this country is yours. Do not be enticed with the dirty coins of silver, be disciplined and remain committed to the efforts and values of this great nation.
To all churches and religious organisations in Zimbabwe we call upon your congregations to pray for our country and preach the gospel of love, peace and unity and development. To both our people and the world beyond our borders, we wish to make this abundantly clear this is not a military takeover of government. What the Zimbabwe defence forces is doing is to pacify a degenerating political, social and economic situation in our country which if not addressed may result in violent conflict.
We call upon all the war veterans to play a positive role in ensuring peace, stability and unity in the country. To members of the Zimbabwe Defence Forces, all leave is cancelled and you are all to return to your barracks with immediate effect.
To the other security forces, we urge you to cooperate for the good of our country. Let it be clear we intend to address the human security threats in our country. Therefore any provocation will be met with an appropriate response.
And to the media, we urge you to report fairly and responsibly. We thank you.”
Gen Chiwenga said the army was prepared to act to end purges within Mr Mugabe’s Zanu-PF party.
Tensions were raised further on Tuesday when armoured vehicles were seen taking up positions on roads outside Harare, although their purpose was unclear.
Some staff at ZBC were manhandled when soldiers took over their offices in Harare late on Tuesday evening, sources told Reuters.
Workers were told that they “should not worry”, a source added, and that soldiers were only there to protect the site.
The BBC’s Shingai Nyoka, in Harare, said the sounds of heavy gunfire and artillery had been heard in northern suburbs where a number of government officials, including the president, live.
Gunfire was heard near Mr Mugabe’s residence in the suburb of Borrowdale early on Wednesday, a witness told AFP news agency.
Zimbabwe Army General Constantino Chiwenga warned of a military takeover
Mr Mugabe sacked Vice-President Emmerson Mnangagwa last week, amid a row over succession.
Mr Mnangagwa had previously been seen as an heir to the president, but First Lady Grace Mugabe is now the clear front-runner.
The rivalry between Mrs Mugabe and Mr Mnangagwa has split Zanu-PF.
Last month, Mrs Mugabe warned of a possible coup plot, saying allies of Mr Mnangagwa were threatening the lives of those who didn’t support him.
The Zanu-PF party said Gen Chiwenga’s comments were “calculated to disturb national peace… [and] incite insurrection”.
The party said it would never succumb to military threats, and that it “reaffirms the primacy of politics over the gun”.
The leader of Zanu-PF’s youth wing, Kudzai Chipanga, said the general did not have the full support of the entire military.
“It is our country and future at stake and we will not let any individual military man interfere with the leader of the party and legitimately voted president of this country,” he told reporters on Tuesday.
The youth wing is a strong supporter of Grace Mugabe.
Grace Mugabe is seen as a potential successor to her elderly husband
Gen Chiwenga’s warning of possible military intervention came on Monday at a news conference at army headquarters where he was surrounded by senior army officers.
He said the “purging” within Zanu-PF was “clearly targeting members of the party with a liberation background”, referring to the country’s struggle for freedom from white minority rule.
“We must remind those behind the current treacherous shenanigans that when it comes to matters of protecting our revolution, the military will not hesitate to step in,” he said.
Mr Mnangagwa is one such veteran of the 1970s war which ended white minority rule.