Riot police in Zimbabwe blocked an address late Tuesday by Prime Minister Morgan Tsvangirai, whose 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. "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.
Zimbabwe's security forces are seen as loyal to Mugabe who shares power with Tsvangirai in an uneasy unity government that was forced 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.
Fresh 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.