The military has seized control in Zimbabwe and has said President Robert Mugabe, in power since 1980, is safe.
After seizing state TV, an army spokesman announced it was targeting people close to Mr Mugabe who had caused "social and economic suffering".
The move came after Mr Mugabe sacked his deputy, Emmerson Mnangagwa, in favour of his wife, Grace.
Heavy gun and artillery fire could be heard in northern parts of the capital Harare early on Wednesday.
A statement read out by a general on air denied it was a coup and said Mr Mugabe was safe but did not say where.
There was no immediate word from Mr Mugabe himself.
Mr Mugabe, 93, has dominated the impoverished country's political scene since independence from the UK.
The UK Foreign Office advised Britons "currently in Harare to remain safely at home or in their accommodation until the situation becomes clearer", while the US embassy in Harare advised US citizens in Zimbabwe to "shelter in place" until further notice.