Dramatic images have been shared by people in Zimbabwe of tanks and military vehicles near the country's capital Harare.

Eyewitnesses said military vehicles were also blocking major roads outside the city and there were reports that troops had surrounded state broadcaster ZBC.

However, Harare's streets remained calm, a day after the armed forces chief said he was prepared to "step in" to end a purge of supporters of a vice president sacked last week.

Witnesses said they saw four armoured vehicles turn before reaching Harare, heading towards the Presidential Guard compound in a suburb called Dzivarasekwa on the outskirts of Harare.

"There were about four tanks and they turned right here, you can see markings on the road," one witness on the Chinhoyi highway said pointing to a road that links up to the Presidential Guard compound that houses the battalion that protects President Robert Mugabe.

Others shared images and videos on social media as speculation mounted about what was happening. ​

As speculation mounted about what the military was planning, Mr Mugabe, the only leader Zimbabwe has known in its 37-years of independence, chaired a weekly meeting in the capital.

The military movement comes amid rising tensions between the southern African nation's military and the ruling Zanu-PF party, headed by the president.

Mr Mugabe plunged the country into political crisis by sacking his vice president Emerson Mnangagwa, 75, last week.

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The long-serving veteran of Zimbabwe's 1970s liberation wars, had been viewed as a likely successor before the president fired him.

His downfall appeared to pave the way for his wife Grace to succeed her 93-year-old husband.

Earlier this week, Zimbabwe’s top general warned that the military would not hesitate to step in to end purges against former liberation war fighters including Mr Mnangagwa, who is known as the "crocodile" because of his perceived shrewdness.

“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,” said General Constantino Chiwenga in a statement.

“The current purging ... targeting members of the party with a liberation background must stop forthwith”.

Army tanks seen heading towards capital Harare, Zimbabwe

The commander of Zimbabwe Defence Forces and political ally of Mr Mnangagwa, added that the Zanu-PF had been hijacked by people who did not fight in the 1970s liberation war, which some commentators read as a criticism of Ms Mugabe, a vocal critic of the former vice president.

In response, the party's Youth League accused the military chief of subverting the constitution.

"We will not fold out hands to allow a creature of the constitution to subvert the very constitution which establishes it," said Kudzai Chipanga.

"Defending the revolution and our leader and president is an ideal we live for and if need be it is a principle we are prepared to die for," he added. ​