The southern African country holds joint presidential, parliamentary and council elections on March 29 in which Mugabe faces former ally Simba Makoni and long-time rival Morgan Tsvangirai, leader of the main opposition Movement for Democratic Change.

Retired Major General Paradzayi Zimondi, who now heads the prison service, which is part of the Zimbabwe Defence Forces, said he would retire to his farm if Tsvangirai or Makoni were elected to lead the country.

"I will only support the leadership of President Mugabe," Zimondi was quoted by the state-owned Herald newspaper while conferring new ranks to senior officers.

"I am giving you an order to vote for the President," he told the officers.

On the eve of the 2002 presidential elections, the country's defence forces chiefs, including Zimondi, said they would not recognise the presidency of anyone who did not participate in the country's 1970s war of independence.

This was taken as a reference to Tsvangirai, a former trade unionist, who did not fight in the liberation war.

Zimbabwe's senior military officers fought against white minority rule and the opposition has in the past accused them of siding with 84-year-old Mugabe, who has been in power since 1980 and is seeking another five-year term.

Mugabe has branded Makoni a political prostitute and Tsvangirai a puppet of former colonial power Britain and has promised a landslide victory to shame his Western critics.