Zimbabwe president Robert Mugabe has urged supporters of his Zanu-PF party to be defiant after he was re-elected as party leader for another five years.

The 85-year-old told up to 10,000 supporters at a rally in Harare that the country's unity government had a short life.

Mr Mugabe said the Zanu-PF party had to win back a majority at the next parliamentary elections.

A date for elections has yet to be set but the power sharing agreement with the Movement for Democratic Change comes to an end next year.