Armoured vehicles have been spotted heading towards Harare, Zimbabwe‘s capital, a day after the army commander threatened to “step in” to calm political tensions over President Robert Mugabe‘s sacking of his deputy.

Eyewitnesses said military vehicles were also blocking major roads outside the city, with the ruling ZANU-PF party, led by Mr Mugabe, accusing the head of the army, General Constantino Chiwenga, of “treasonable conduct”.

Mr Mugabe – the only leader Zimbabwe has known in 37 years of independence – sparked a rift with the military by sacking his Vice President Emerson Mnangagwa, 75, last week. The long-serving veteran of Zimbabwe’s 1970s liberation wars had been viewed as a likely successor to the President.

However, his downfall appeared to pave the way for Mr Mugabe’s wife, Grace, to succeed her 93-year-old husband.

Mr Mnangagwa, who enjoyed the backing of the military, fled the country and said he and his family had been threatened. Over 100 senior officials allegedly supporting him have been listed for disciplinary measures by a faction associated with Ms Mugabe.

On Monday, General Chiwenga 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 Chiwenga in a statement.

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

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 conflict, which some commentators read as a criticism of Ms Mugabe: a vocal critic of the former Vice President.

In response to the General’s words, ZANU-PF issued a statement accusing the commander of “treasonable conduct”, saying his comments were “clearly calculated to disturb national peace and stability” and were “meant to incite insurrection”. It was not clear whether the commander still had his post.

Zimbabwe's Information Minister gives statement on Vice President Mnangagwa being discharged

State broadcaster Zimbabwe Broadcasting Corporation read out part of the ruling party statement late in the nightly news, which was led by a report on regional tourism, but refrained from publishing General Chiwenga’s statement.

The Herald newspaper, which had initially posted some of his comments on its official Twitter page, deleted the posts without explanation.

A number of people posted images of the military vehicles on the road to the capital on social media. Some called it “a coup”. The Independent was unable to verify where the military vehicles were travelling to and for what purpose.

Earlier in the day, ZANU 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.

The rising political tension comes at a time when Zimbabwe is struggling to pay for imports due to a dollar crunch, which has also caused acute cash shortages.

Army tanks wait just outside of Zimbabwe capital Show all 4 1 /4 Army tanks wait just outside of Zimbabwe capital Army tanks wait just outside of Zimbabwe capital Military vehicles just outside Harare REUTERS Army tanks wait just outside of Zimbabwe capital Soldiers stand beside military vehicles just outside Harare REUTERS Army tanks wait just outside of Zimbabwe capital Tanks just outside Harare Reuters Army tanks wait just outside of Zimbabwe capital Military vehicles parked just outside of Zimbabwe capital Reuters

While Mr Mugabe’s rule has been anchored by support from the military, the ageing leader does not tolerate public challenges.

In the past, Mr Mugabe has warned military commanders from interfering in ZANU-PF succession politics. “Politics shall always lead the gun, and not the gun politics. Otherwise it will be a coup,” he told supporters in July.

The country was shaken last year by the biggest anti-government protests in a decade, and Mugabe’s appointment of a minister for cybersecurity last month was criticised by activists as a crackdown on social media users.

However, it was thought that he would go into next year’s elections with military support, but war veterans broke ranks with him in 2016 and have vowed to form a broad front with the opposition to challenge his long rule.