- Report records hundreds of rape cases
* Youth militia and war veterans implicated
* Calls for ICC probe, regional pressure
* MDC says failure to prosecute a breach of unity pact
JOHANNESBURG, Dec 10 (Reuters) - Zimbabwe's 2008 elections were marred by the widespread rape of political opponents by President Robert Mugabe's supporters, according to a report released by an HIV/AIDS advocacy group on Thursday.
Mugabe was outpolled by bitter rival Morgan Tsvangirai in a first round presidential vote, as his ZANU-PF party lost its parliamentary majority for the first time since independence in 1980. Mugabe, however, secured re-election in a controversial run-off poll after Tsvangirai pulled out citing violence against his supporters.
Tsvangirai's MDC party says about 200 of its supporters were killed in politically motivated violence.
The report prepared by AIDS-Free World says Mugabe's supporters, including youth militia and some veterans of Zimbabwe's 1970s independence war, "committed widespread, systematic rape in 2008 to terrorize the political opposition."
Officials from Mugabe's ZANU-PF, who routinely deny allegations that the party has sanctioned the use of violence in election campaigns, were not immediately available to comment.
AIDS-Free World said the 64-page report -- entitled "Electing to Rape" -- is based on interviews with 72 survivors and witnesses, and documents 380 rapes committed by 241 perpetrators across Zimbabwe's 10 provinces.
"ZANU-PF orchestrated its campaign of rape to terrorise, and destabilize entire communities," said Paula Donovan, co-director of AIDS-Free World. "Clearly, the tactic worked: Mugabe is still president."
The 85-year-old leader was forced into a power-sharing government with Tsvangirai, who is now prime minister, following widespread condemnation of the violence that marred his re-election.
The unity government has overseen the restoration of relative political and economic stability since its formation in February, but analysts say the situation remains fragile amid in-fighting between the coalition partners.
Western donors, seen as key in providing the more than $10 billion the new government says is required to rebuild Zimbabwe's battered economy, have demanded broad political reforms before injecting direct funding.
AIDS-Free World called for an International Criminal Court probe into the alleged sexual crimes and urged regional pressure on Zimbabwe to bring the perpetrators to justice.
"The evidence is incontrovertible: Mugabe believes he can sanction rape without fear of consequences. Zimbabwe is perhaps the greatest test for ending impunity," AIDS-Free World co-director Stephen Lewis, a former UN special envoy on HIV/AIDS in Africa, said.
A senior official from Tsvangirai's party said that while some perpetrators of political violence had been brought to the courts and convicted, the slow pace of prosecutions was another sign of Mugabe's reluctance to fulfil the power-sharing pact.
"In terms of the global political agreement, the police and the attorney-general's office were supposed to expedite the investigation and prosecution of all political violence cases," the MDC's deputy Minister of Justice, Jessie Majome, told Reuters.
"There is no sign of urgency on the matter and this is yet another breach of the (power-sharing) agreement. The justice ministry has no constitutional powers to force the attorney-general to prosecute." (Reporting by Johannesburg newsroom) (For more Africa cover visit: http://af.reuters.com -- To comment on this story email: SouthAfrica.Newsroom@reuters.com)