Zimbabwe's opposition leader Morgan Tsvangirai hailed on Saturday the decision by Kenya's top court to order a new presidential election as a "step towards democracy".
Tsvangirai, the leader of the Movement for Democratic Change (MDC), has made three failed attempts at the presidency, losing all of them to long-ruling leader Robert Mugabe.
"This is an unprecedented decision in the whole of Africa and I think it's a good step towards democracy," Tsvangirai told thousands of supporters at a rally organised by an alliance of opposition parties.
In 2008, Tsvangirai beat Mugabe in the first round of voting but failed to secure an outright majority, leading to a run-off. He later pulled out of the second round, due violence against his supporters.
The MDC is now part of an opposition alliance formed ahead of the 2018 vote, in a bid to unseat the 93-year-old Mugabe.
The Saturday rally in Bulawayo, Zimbabwe's second city, was the first gathering of the alliance since its formation last month.
Tsvangirai told supporters that there should be "clear reforms" in place ahead of the next election to avoid disputes.
Past elections in Zimbabwe have been marred by violence, intimidation and charges of electoral fraud.
Kenya's Supreme Court nullified on Friday the results of last month's presidential election which handed victory President Uhuru Kenyatta, citing irregularities in the electronic transmission of vote results.