Zimbabwe President Emmerson Mnangagwa has promised to investigate a brutal crackdown by security forces on anti-government protesters, as two of his supporters spoke of a possible plot to remove him from office.
Lawyers and activists say police and soldiers have killed at least a dozen people, wounded many others and arrested hundreds since demonstrations began nine days ago following a rise in the price of fuel.
Zimbabwe's Human Rights Commission (ZHRC) has even accused security forces of systematic torture.
Mnangagwa said violence by security forces was "unacceptable and a betrayal of the new Zimbabwe."
"Misconduct will be investigated. If required, heads will roll," Mnangagwa wrote on Twitter on Tuesday, calling for a "national dialogue" involving churches, civil society and the opposition.
A lawyers group reported more rights violations since Mgangagwa's return to Harare on Monday, fuelling rumours of deep divisions within his government.
Two allies of Mnangagwa - a lawmaker of his ZANU-PF party, Mayor Wadyajena, and former deputy finance minister Terence Mukupe, said some members of the government were attempting to impeach him.
"They threatened to kill me and harm my family. I stand by @edmnangagwa... The plot is foiled, they lack numbers for impeachment," Wadyajena posted.
A spokesman for Mnangagwa had said on Sunday the crackdown was a foretaste of how authorities would respond to future unrest.
The ZHRC said on Tuesday that security forces instigated systematic torture of residents after last week's unrest - during which police say three people died - turned violent.
The level of force used on those who died or were injured, and supported by medical reports, pointed to police brutality, a ZHRC commissioner said.
Mnangagwa said on Tuesday that the 150 per cent hike in the price of fuel that triggered the demonstrations had been necessary.
South African President Cyril Ramaphosa, speaking in Geneva, said his government was in discussions with Harare about how best to help.
He called for sanctions against Zimbabwe to be lifted to help ease shortages of food and fuel, "because they have embarked on a path of democracy and on a path of real recovery."
Australian Associated Press