Soldiers and police fanned out across Zimbabwe on Tuesday ahead of a general strike called by the opposition to pressure officials to release the results of a presidential election.

Army trucks, some equipped with water cannons, moved through opposition strongholds around the capital Harare and riot police and other officers set up checkpoints.

"This is a routine security exercise," one police officer said at a checkpoint in a township controlled by the opposition Movement for Democratic Change (MDC), which has called on Zimbabweans to stay at home indefinitely.

Morgan Tsvangirai's MDC has declared victory in the March 29 parliamentary and presidential elections and has demanded that President Robert Mugabe step down. Parliamentary results have been released but the results of the presidential poll have not.

Zimbabwe's electoral commission said it was still counting and verifying the votes.

On Monday, a Zimbabwean High Court rejected the MDC's bid to force authorities to release the results.

The MDC said one of its supporters was stabbed to death by members of Mugabe's ruling ZANU-PF party. Police disputed that, saying the killing did not appear to be politically motivated.

Tsvangirai and his supporters are hoping that Zimbabweans will support the general strike. But there are concerns it could fizzle as others have in the past or wither in the face of the unspoken threat of a police crackdown.

"The Zimbabwe Republic Police has noted with concern the distribution of subversive fliers and pamphlets by the MDC Tsvangirai faction urging for an indefinite stay-away ... we find the call by the MDC Tsvangirai faction as agitating for violence," police spokesman Wayne Bvudzijena said.

Mugabe's police beat dozens of MDC members and supporters, including Tsvangirai, during an aborted 2007 anti-government protest. A general strike last year to protest wages and living conditions also collapsed.

Zimbabweans are facing inflation of more than 100,000 percent, an unemployment rate of 80 percent and rising poverty and malnutrition. There are chronic shortages of food, fuel and hard currency throughout the country.

POLITICAL STALEMATE

The opposition has accused Mugabe's ZANU-PF of working behind the scenes to delay the announcement of the presidential results to give them time to organise a violent response to their biggest electoral setback since coming to power in 1980.

Official results show ZANU-PF lost control of parliament on March 29, and independent observers have said that Tsvangirai outpolled the 84-year-old veteran leader but did not win enough votes to avoid a second-ballot run-off.

The stalemate has stoked international fears of violence in Zimbabwe. Britain and the United States have called for the speedy release of the results and warned Mugabe's government not to intimidate opponents.

Southern African leaders said after a summit in Lusaka at the weekend that the results should be released "expeditiously".

But further delays are expected because of legal manoeuvres and a recount in constituencies ordered by election officials for next Saturday. The MDC is challenging that decision.

The MDC also filed an application on Monday asking the electoral court to set aside results in about 60 parliamentary seats won by ZANU-PF. The move came after ZANU-PF launched its challenge of results in about two dozen seats won by the MDC.

The MDC accuses ZANU-PF of vote-buying, intimidating and interfering with presiding election officers and other malpractices. ZANU-PF has accused the MDC of similar election wrongdoing.