Harare, Zimbabwe ? Soldiers took to the streets with armored cars and water cannons Friday as Zimbabwe’s security chiefs warned that they were ready to confront any violence during the weekend’s crucial presidential election in this economically wrecked African nation.

The opposition urged its supporters to defend their ballots against what they have charged is a plot by the ruling party to rig today’s vote.

President Robert Mugabe, the 84-year-old revolution leader facing the toughest challenge since he won power in 1980, told his final campaign rally that the election would show Zimbabweans’ opposition to former colonizer Britain, which he accuses of supporting the opposition.

“Zimbabweans are making a statement against the meddling British establishment,” the president told about 6,000 people in Epworth, an impoverished town outside the capital of Harare.

Mugabe called for discipline at the polls despite “provocation from outsiders who are already claiming the elections are not free and fair.”

Running against Mugabe are opposition leader Morgan Tsvangirai, 55, who narrowly lost the disputed 2002 election, and former ruling party loyalist and finance minister Simba Makoni, 58. Preliminary results are not expected until Monday.

Tsvangirai urged opposition supporters to stay at polling stations until they close and counting begins.

“They would not rig in front of you,” he told about 4,000 people in Domboshawa, a farming community north of Harare. “We have won this election already. What’s left is for us to defend our vote.”