Zimbabwean Army General Constantino Chiwenga deploys soldiers outside Harare

Zimbabwean Army General Constantino Chiwenga, Commander of the Zimbabwe Defense Forces, addresses a media conference held at the Zimbabwean Army Headquarters on November 13, 2017 in Harare. (Photo by AFP)

Zimbabwe was on edge Tuesday as armored personnel carriers were seen outside the capital a day after the army commander threatened to "step in" to calm political tensions over the president's firing of his deputy.

The Associated Press saw three armored personnel carriers with several soldiers in a convoy on a road heading toward an army barracks just outside the capital, Harare.

While it is routine for armored personnel carriers to move along that route, the timing heightened unease in this southern African country that for the first time is seeing an open rift between the military and 93-year-old President Robert Mugabe. The military has been a key pillar of Mugabe's power since independence from white minority rule in 1980.

Mugabe last week fired Vice President Emmerson Mnangagwa and accused him of plotting to take power, including through witchcraft. Mnangagwa, who enjoyed the backing of the military and was once seen as a potential successor to Mugabe, 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 Mugabe's wife, Grace Mugabe.

The first lady, whose political profile has risen in the past few years, now appears positioned to replace Mnangagwa at a special conference of the ruling party in December, leading many in Zimbabwe to suspect that she could succeed her husband as president.

On Monday, army commander Constantino Chiwenga issued an unprecedented statement saying purges against senior ruling ZANU-PF party officials linked to the 1970s liberation war should end "forthwith."

"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," the army commander said.

Mugabe did not respond to the military statement, and government spokesman Simon Khaya Moyo said only the president could respond. The state-run broadcaster did not report on the statement.

The ruling party's youth league, aligned to the first lady, on Tuesday criticized the army commander's statement, saying youth were "ready to die for Mugabe."

The army spokesman was not immediately available for comment Tuesday. State broadcaster Zimbabwe Broadcasting Corporation was operating as usual and the capital remained calm.

Frustration has been growing in once-prosperous Zimbabwe as the economy collapses under Mugabe, the world's oldest head of state. 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 criticized by activists as a crackdown on social media users.