Staff at Robert Mugabe's Harare mansion were detained without food or water and questioned for hours this week by military officers who pressed them for information on recent meetings held by the former president, reports from Zimbabwe said on Friday.

Four security staff, including chief security officer Funny Mpofu were taken for questioning at an army barracks in Harare on Wednesday morning and only released at the end of the day, reports the Zimbabwe Independent.

Grace Mugabe 'anxious'

The paper said the staff were questioned about "the visitors Mugabe has been receiving and the agenda of their meetings".

Mugabe was not at the house at the time, having gone to South Africa to visit his sons. Former first lady Grace Mugabe, who stayed behind, was said to be "very anxious and not sure whether to remain there", an unnamed security officer told the Independent.

Mugabe caused a stir in the ranks of the ruling Zanu-PF after he held a meeting on Sunday with former cabinet minister Ambrose Mutinhiri, who quit the ruling party to head a new party with links to Mugabe and his allies.

Mutinhiri said he resigned from Zanu-PF in protest against last year's "military coup" that led to Mugabe's resignation.

The meeting has fuelled speculation that Mugabe could be planning a political comeback, which would spoil President Emmerson Mnangagwa's chances of unifying Zanu-PF supporters in Mugabe's former rural strongholds ahead of polls later this year.

The private Daily News said that a total of four of Mugabe's staffers were detained on Wednesday.

No food or water

"The workers were denied access to food or water and they were being asked names of the people who have been visiting the former president," an unnamed source told the paper.

In another report, a source told the private NewsDay: "The interrogations were centred on who visits the former president, how (the workers) spend the day and if the ex-president discusses politics. Basically, they wanted to know the thinking of the old man and his plans."

There's been no word from the government on the alleged detention of Mugabe's staff. Zanu-PF spokesperson Simon Khaya Moyo told NewsDay that he had "no information" on the episode.