John Makumbe, a fierce critic of Zimbabwe's President Robert Mugabe and leading pro-democracy activist, has died, the Movement for Democratic Change party said Monday.

Makumbe, 64, a University of Zimbabwe political scientist, collapsed at his home Sunday and later died at a local hospital in the capital Harare.

At the time of his death, he was working towards entering mainstream politics with plans to contest parliamentary elections this year, on the ticket of Prime Minister Morgan Tsvangirai's MDC party.

Even as activists and political opponents were targeted by the Harare regime, Makumbe fearlessly lashed out at Mugabe in independent newspaper columns and in analytical comments to journalists.

The Zimbabwe Lawyers for Human Rights praised Makumbe for his "contribution to fighting injustice, standing up to dictatorship."

Makumbe's colleague at the university, Lovemore Madhuku, said "he was courageous to face authorities, criticising their bad deeds."

As an albino, Makumbe also campaigned against the discrimination and persecution of people with albinism in many African countries.