HARARE, Zimbabwe (AP) -- One campaign ad on the Internet shows video footage of a lawmaker in Zimbabwe's tenuous coalition government punching a Cabinet minister appointed by President Robert Mugabe. Another ad attacks the president's rival and coalition partner, Prime Minister Morgan Tsvangirai, with a clip of him defending gay rights, an unpopular stance in many sectors of Zimbabwean society, during a television interview.
Ahead of a vote Saturday on a new constitution, Zimbabwe's main political camps are urging their supporters to approve it, making the outcome all but certain. But you wouldn't know they were in agreement from the tone of some campaigning, which amounts to a test run for national elections slated around July, a high-stakes event expected to end coalition rule and determine whether Mugabe retains his tight grip after decades in power.
The referendum this weekend mirrors the hopes and fears of four previous elections which were marred by violence and vote-rigging since Tsvangirai, a former labor leader, founded his Movement for Democratic Change party, the first real challenge to Mugabe, in 1999.
Already, tensions erupted in the volatile western Harare township of Mbare on Friday. An alliance of rights groups said eight supporters of the Zimbabwe prime minister's party were assaulted while putting up 'Vote Yes' posters for Saturday's poll.
The Crisis Coalition said injured victims of the Friday attack included future parliamentary candidate Sten Zvorwadza.
A visiting British Broadcasting Corp. news crew witnessed the assault.
BBC correspondent Andrew Harding said "an increasingly large and agitated crowd" tried to grab the crew's camera, threw dirty water at the journalists and punched them on their arms and backs without inflicting serious injuries.
The Mbare township has recently been the scene of violence blamed on a youth gang known as Chipangano, or, in the local Shona language, brotherhood, a group loyal to Mugabe.
Nelson Chamisa, a Tsvangirai party official, said the "complicit police" failed to stop the assault.
"The ghost of violence has reared its ugly head. We were expecting a peaceful referendum but once again the safety of the voter and the vote is no longer certain," he told The Associated Press.
All political groups have called for a 'Yes' vote on a constitution whose reforms would reduce presidential powers and grant more democratic rights. However, even if the constitution is approved, arrests and harassment of rights and democracy activists this year by police loyal to Mugabe raise doubts about whether such changes would be seriously enforced.
The draft constitution, for example, imposes a limit of two five-year terms on the office of president but it is not retroactive, enabling Mugabe to rule for two more terms to age 99 if he were to win the next two elections.
Mugabe's loyalists have posted United States-style presidential campaign advertisements on the Internet claiming that Tsvangirai's Movement for Democratic Change Party even resorts to violence by punching and assaulting members of the Harare parliament while Mugabe spurns violence. Gay rights have been rejected by Mugabe, an outspoken critic of same sex partners he has described as "lower than pigs and dogs," a well-received stance in many generally homophobic African communities.
Tsvangirai denies unequivocal support for gay rights but says the new constitution being voted on Saturday enshrines broader protection for equal rights among all Zimbabweans.
He has recently been on a high-profile campaign of daily rallies in favor of the referendum, while Mugabe has only touched briefly on the referendum at small public engagements.
Slick ads on YouTube and other sites implore Zimbabweans to "Think Before You Vote" for the country's next president later in the year. Mugabe had ruled virtually unchallenged until Tsvangirai launched his opposition party. Mugabe's loyalists have been blamed for most violence in a decade of political and economic turmoil.
At least one third of Zimbabwe's population of 12 million is estimated to have Internet access through mobile phones.
To woo younger support, Mugabe, 89, has also appeared in a new pop music video on state television with a singing group called the Born Free Crew, symbolizing young Zimbabweans born after he led the nation to independence. The ascetic Mugabe, dressed in a business suit, dances awkwardly with the young African rappers in denims with roughed-up hair shaven into strips and zig-zags.
Mugabe then sings "Zviri sei sei" in the local Shona language, street slang for "Hey, how's it going?"
The state Electoral Commission said mobile phones won't be allowed Saturday into the 9,400 polling stations in case voters photograph their ballot papers. This was seen in this month's Kenya presidential race so that voters could prove to their leaders how they balloted, said the acting head of the Zimbabwe election body, Joyce Kazembe.