The ruling ZANU-PF party says neither President Robert Mugabe nor his rival, Morgan Tsvangirai, won the necessary absolute majority and a run-off will be necessary.

Tsvangirai's Movement for Democratic Change (MDC) says it won both the presidential and parliamentary elections. It accuses Mugabe of rolling out military forces across Zimbabwe to try to extend his 28-year rule in a de facto coup.

The two-week delay in releasing the presidential results from the March 29 election has heightened tension in the southern African nation, whose economy has collapsed.

The Zimbabwe Electoral Commission has ordered recounts in 23 constituencies, raising the possibility ZANU-PF could overturn its defeat in the parliamentary poll held on the same day.

MDC lawyer Selby Hwacha accused the ZEC of calling the recount to help ZANU-PF rig the poll and said the MDC would launch a legal challenge on Tuesday -- possibly prolonging the deadlock.

The government tried on Sunday to ease concerns the military might intervene to try to keep Mugabe in power.

"The soldiers are in the barracks where they belong because the country does not fully require their services in such a peaceful environment," the Sunday Mail quoted Information Minister Sikhanyiso Ndlovu as saying.

"I believe everyone in the country is aware that there is no military junta."

Zimbabwe's generals occupy no official posts in its ruling party, but the heads of the army and security forces are thought to have been key planners in an emerging strategy for Mugabe, 84, to fight back after elections handed him his biggest defeat since taking power.

Tsvangirai, who says he is a prime target of government security and military forces, has said widespread violence could erupt unless other African states intervened.

Human rights organisations and the opposition say Mugabe has unleashed a campaign of systematic violence in response to ZANU-PF's first electoral defeat.

The MDC has called for an indefinite general strike on Tuesday to put pressure on Mugabe and push for poll results to be released.

But the veteran leader keeps digging in. He snubbed a regional weekend summit in Lusaka that called for the rapid verification and release of results and urged Mugabe to ensure any run-off would be held "in a secure environment".

Zimbabweans had hoped the poll would bring relief from a deepening economic crisis. A quarter of the population have fled to escape hyper-inflation of more than 100,000 percent, chronic shortages of food and fuel and 80 percent unemployment.