Ammon News - (Al Jazeera) - Zimbabwe's main opposition party has launched its presidential election campaign, a few days after incumbent President Robert Mugabe began his re-election bid for the July 31 national vote.

Prime Minister Morgan Tsvangirai, party leader and main candidate for the Movement for Democratic Change, had earlier asked for a delay of at least 25 days to give time to institute democratic reforms and changes to electoral laws to allow for a free and fair ballot.

Tsvangirai is Mugaba's principal rival in the presidential vote.

Mugabe's partners in the coalition had also appealed against the July election, but the Constitutional Court, the nation's highest court, upheld the date on Thursday.

Mugabe said on Friday that his ZANU-PF party would put up a "fight of our lives'' to regain waning support in urban areas, strongholds of Tsvangirai, and extend his 33-year rule.

"You are our soldiers, you have a battle to fight. Go into the battle well-armed," he said as he launched an attack on
the 15-nation Southern African Development Community which had asked him to delay elections.

Economy concerns

"Go into the battle with the full knowledge that there is a political enemy. This is a do or die struggle."

The 89-year-old president, who was forced to form a tenuous coalition government with Tsvangirai by regional leaders after violent and disputed elections in 2008, has ruled the country since independence from colonial rule in 1980.

Mugabe's party has been repeatedly accused of political violence, intimidation and vote-rigging in the past three general elections since 2000.

Al Jazeera's Haru Mutasa, reporting from the site of the opposition campaign launch in Marondera, said that most voters wanted the election to be over and done with.

She said that the main issues voters would be looking at was the economy and many hoped that the elections were free and fair.

Mugabe set the national vote date for July 31 after a May court ruling which ordered him to call for early polls.