Police have imposed a three-month ban on political rallies and protests in parts of Zimbabwe's capital to try to calm tensions, after recent violence.
The police set up road blocks around the rally venue on Sunday
The police said there was "pandemonium and looting" on Sunday when they halted an opposition rally.
The opposition have likened the move to "a state of emergency" and said the government of Zimbabwe was panicking.
President Robert Mugabe has said he has no intention of stepping down, in an interview to mark his 83rd birthday.
In the rambling hour-long television interview, Mr Mugabe also criticised colleagues who have been debating when he will retire and who should replace him.
The state-run Herald newspaper devoted 16 pages of pictures and congratulatory messages to Mr Mugabe in its Wednesday edition.
Mr Mugabe retains an iron grip after nearly 27 years in power. His supporters are preparing a large party in the central city of Gweru at the weekend to mark his birthday and have sought donations from the population.
But critics say this is a huge waste of money, when so much of the population is impoverished.
On Sunday, police used tear-gas and water cannon to prevent an opposition rally from going ahead in the Highfield township in the capital, Harare, despite a ruling by the High Court that it should be allowed.
Opposition supporters who have spoken to the BBC say the police also chased and beat people, including innocent by-standers.
There were several arrests. The police have been out in force in Harare suburbs since then.
They say the ban is necessary to prevent further disorder.
Mr Mugabe said in his interview that those jockeying to replace him were resorting to nonsense.
Robert Mugabe admitted the standard of living had declined
He said there would come a day when he would go but it was not now.
"Can you see any vacancies? The door is closed," he told his interviewer.
People could talk about the process of succession, he said, but not with a view to pushing him out of office now.
And he had some sharp words for those who might be in the running to succeed him.
President Mugabe said there were high-ranking, ambitious people who were looking at themselves.
Asked about Zimbabwe's deepening economic crisis, Mr Mugabe denied that the economy was sinking, though he admitted that there was a decline in the standard of living.
Last week, the annual rate of inflation shot up to nearly 1,600%.
The BBC's Southern Africa correspondent Peter Biles says Mr Mugabe's comments are unlikely to offer much comfort to ordinary people, whose daily lives have become a struggle for survival.