TIMELINE - Zimbabwe's decade of crisis

(Reuters) - Zimbabwe's Robert Mugabe, in power since 1980, faces a tough challenge in Saturday's presidential vote being held alongside parliamentary and municipal ballots.

Following is a chronology of Zimbabwe's decade of troubles:

1998 - An economic crisis marked by high interest rates and inflation provokes riots and increasing support for the Zimbabwean Congress of Trade Unions headed by Morgan Tsvangirai.

1999 - The opposition Movement for Democratic Change (MDC) is formed and Tsvangirai is appointed leader.

2000 - Voters back the MDC and turn down a proposed constitutional amendment which would have given the president more power.

-- Mugabe's ruling ZANU-PF wins a parliamentary election amid charges of fraud and vote-rigging by the opposition.

-- Thousands of independence war veterans and their allies, backed by the government, seize white-owned farms, saying the land was illegally appropriated by white settlers.

2001 - Government agrees to stop often violent land invasions in exchange for British funds to finance land reform. Mugabe later rejects criticism he has ignored the deal.

2002 - Mugabe wins election pitting him against Tsvangirai. Observers condemn poll as flawed and unfair. Commonwealth suspends Zimbabwe.