Registered: Mar 2004
Local time: 03:13 AM
Location: The Historic City of Portsmouth, England
The leader of the main opposition party in Zimbabwe, Morgan Tsvangirai, and several colleagues have been detained.
They were seized after trying to hold a prayer meeting that the government said breached a ban on political gatherings.
Riot police sealed off roads in Harare and used tear gas and water cannons as they fought running battles with activists, opposition officials said.
The rally had been called by the Save Zimbabwe Campaign - a coalition of groups agitating for political change.
Officials for the Mr Tsvangirai's party, the Movement for Democratic Change, told the BBC that he was being held with five other senior members of the leadership at Highfield police station.
MDC spokesman Eliphas Mukonoweshuro said the protesters were not doing anything wrong.
"It was not a political rally, therefore it was not subject to the provisions of the public order and security act, and there was no permission required to be obtained from the police," he told the BBC.
"But the police went ahead and arrested a broad cross section of leaders of civic organisations, political parties, labour and students."
The three-month ban on political meetings was imposed after violence at an opposition rally last month.
A Save Zimbabwe Campaign statement said lawyers were being denied access to detained supporters. It also accused police of forcing shops, bars and churches to shut down for the day.
"Highfield has been turned into a war zone," it said.
Robert Mugabe, who has led Zimbabwe since independence in 1980, retains an iron grip on power.
Last month, in an interview to mark his 83rd birthday, the veteran president said he had no intention of stepping down.
However civil discontent is rising over the economic crisis, with chronic unemployment and inflation running at more than 1,700% - the highest in the world.
Once the breadbasket of southern Africa, Zimbabwe has had to rely on food imports as agricultural production collapsed after the seizure of white-owned farms was speeded up seven years ago.
Another controversial move, the clearance of slum areas in 2005, left an estimated 700,000 people homeless and affected many more.
A UN report called it inhumane and said it had caused immense suffering among the most vulnerable sections of society.