Zimbabwe's leader of the Movement for Democratic Change (MDC), Morgan Tsvangirai, argues with a policeman after being refused to hold a rally in Harare, 18 Feb 2007

Police used tear gas and water cannons to disperse opposition supporters who arrived for an opposition rally in a poor township of Harare, and witnesses say hundreds of people were arrested.

Riot police barricaded the area in defiance of a High Court order to allow the rally to take place. The court overruled a police ban on gatherings. The police had argued they did not have sufficient manpower or time to secure the event.

The founder of the opposition Movement for Democratic Change, Morgan Tsvangirai, was planning to announce his candidacy for next year's presidential elections, during the rally.

In the city of Bulawayo on Saturday, MDC parliament member David Coltart said police attacked and arrested several people taking part in what was billed as a "defiance campaign," led by academic Arthur Muutambara, who heads another faction of the MDC.

Welshman Nucbe, of Muutambara's faction, said Home Affairs Minister Kembo Mohadi told him Friday that security ministers had decided to ban opposition gatherings because of rising tensions in the country.

With dramatically rising inflation, at nearly 1,600 percent a year, opposition to President Robert Mugabe and his ruling ZANU-PF party has recently spread far beyond the two factions of the MDC.

In the past two weeks, analysts say, there were more spontaneous protests, labor disturbances and arrests than at any time in the past four years.

Veteran Zimbabwe political analyst Brian Raftopoulos says there is a rising tide of discontent. He said the Zimbabwe government now has few options open to it to resolve the economic and political crisis.