Riot police in Zimbabwe have blocked an address by MDC leader and Prime Minister Morgan Tsvangirai ahead of the coming months' elections.
Tsvangirai's uneasy unity rule with President Robert Mugabe is set to end within months at the ballot box.
"Riot police have just disrupted a community meeting I was due to address," Tsvangirai tweeted on Tuesday night. "Their actions today show that the leopard has not changed colours."
A pick-up truck loaded with helmet-clad police officers carrying riot shields and batons could be seen in pictures posted on Tsvangirai's Facebook page.
The meeting was set to start at 6pm in the capital, state-run newspaper the Herald reported on Wednesday. But around 20 riot police ordered people to leave the meeting before it had started.
Police spokesperson Charity Charamba said the meeting was stopped as it was not cleared with authorities.
The area's district police officer "was not given the notice of intention to hold the meeting" as legally required, she was quoted saying.
But, the Movement for Democratic Change (MDC) said the documentation was sent to the police.
"We were unlawfully dispersed," senator Obert Gutu told the Herald, adding that the meeting was to discuss an upcoming vote on a draft constitution.
"For the police to say they dispersed the meeting because it was in the evening, it would be a frivolous excuse," he added.
Zimbabwe's security forces are perceived as loyal to Mugabe who shares power with Tsvangirai in an uneasy unity government that was uneasily formed after chaotic polls in 2008.
Zimbabweans will vote on March 16 in a draft referendum which is set to pave the way for fairer elections.
Polls are set for July to steer Zimbabwe onto a new track after a series of votes were marred by violence, intimidation and economic hardship.
The run-up to the polls has been marked by a crackdown against political activists, media and civil society groups.
Radio stations have been raided, members of non-governmental groups have been arrested and the son of an opposition leader died in a suspected firebomb attack.
Zimbabwe police have found no foul play in the house fire that killed the 12-year-old boy.
Mugabe, who turned 89 on February 21, has ruled the Southern African nation since independence in 1980.
The former rivals set up a unity government in early 2009 after the violent polls of the previous year tipped the country into crisis. – AFP