Zimbabwe's main opposition group says that one of its members has died after being tortured by police officials and soldiers.
The police stopped mass protests from reaching central Harare
Tichaona Kaguru was taken away from the house of a Movement for Democratic Change councillor in Harare, beaten and died while waiting for an ambulance, the MDC says.
The police have arrested more than 300 MDC supporters and officials during this week's strike, intended to drive President Robert Mugabe out of power.
Mr Mugabe, however, says the Movement for Democratic Change protests have flopped because the security forces have prevented the mass demonstrations they had also called.
He also said that the use of force against opposition marchers had been unavoidable even though "we don't want to make our people suffer".
"It's sad when we are forced as government... to have
to use tear gas against our youth, who are being misled," he told South African television.
"But we have to do it in the interest of peace and security."
Most businesses in Harare and the second city, Bulawayo were closed on Wednesday for a third day of strikes, while police maintained tight security.
The BBC's Barnaby Phillips says neither the government nor the opposition has emerged so far as clear winners, so conflict and economic decline may well continue.
The police have launched a door-to-door manhunt for known MDC supporters and are harassing their families
The MDC accuses Mr Mugabe of rigging last year's election and mismanaging the economy.
For his part, the president says they are a front for white farmers and Britain, who are trying to block his land reform programme.
The police said they had no information on Mr Kaguru's reported death.
"The only death that we are aware of is that of a man who was stoned by MDC supporters in (Harare township) Mbare on Monday," a police spokesman told Reuters news agency.
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State television says that security agents are investigating businesses which have shut down during the strike.
The government has threatened to withdraw their trading licences.
Both the European Union and the G8 group of rich countries have, in turn, urged the government to show restraint in their dealings with the opposition and its supporters.
MDC activists and officials have been arrested throughout the country.
An MDC spokesman for Manicaland, Pishayi Muchauraya, told the privately owned Daily News: "The police have launched a door-to-door manhunt for known MDC supporters and they are harassing their families."
On Monday, riot police used tear gas, and soldiers in armoured cars fired guns to break up the demonstrations.
On Tuesday, about 200 people tried to march into Bulawayo city centre but they were soon dispersed by riot police, says the BBC's Themba Nkosi in the city.
The High Court in Harare is considering a government application to tighten bail conditions for MDC leader Morgan Tsvangirai and two other high-ranking MDC officials, all of whom are on trial for treason.