The US envoy to Zimbabwe has said he believes opposition to President Robert Mugabe has reached a turning point.
Morgan Tsvangirai and other MDC leaders have been beaten
Ambassador Christopher Dell said Zimbabweans were "losing their fear" despite the violence carried out against them by the security forces.
He added that there was discontent with Mr Mugabe's rule within the ruling party, the military and the police.
The government has been conducting a crackdown that has included arresting and beating opposition leaders.
Mr Dell said Mr Mugabe had used violence and intimidation to stay in power for 27 years.
"What I think we have seen in the last week is that people have turned a corner," he added.
"They're not afraid any more."
Mr Dell said the violence directed against Zimbabweans was causing a split in the security forces.
He said rank-and-file police officers were increasingly reluctant to carry out such attacks.
The US envoy said this could prompt other leaders in the region to change their attitude towards President Mugabe.
"I think a lot of eyes have been opened in the region in the last couple of weeks and so what we are witnessing is perhaps the beginning of a change on the part of the African neighbours of Zimbabwe as well."
South Africa, which has long pursued a policy of "quiet diplomacy" towards neighbouring Zimbabwe, recently called for President Mugabe to respect human rights.
BBC Southern Africa correspondent Peter Biles says the US, along with Britain, has been at the forefront of international criticism of Zimbabwe.
Zimbabwe has accused Britain and other Western countries of interference.
On Monday Foreign Affairs Minister Simbarashe Mumbengegwi warned foreign envoys in Harare that the government would not hesitate to expel those who backed the opposition.
Zimbabwe's opposition Movement for Democratic Change (MDC) says there has been a sharp escalation in violence against activists across the country.
Scores of activists have been arrested and allegedly assaulted after police broke up a banned rally in Harare on 11 March.
Four senior MDC officials were prevented from leaving the country, some to seek treatment for injuries they say were sustained in police custody.
More than 80% of Zimbabweans are living in poverty, with chronic unemployment and inflation running at more than 1,700% - the highest in the world.