TIMELINE: Key dates in Zimbabwe's crisis

(Reuters) - Zimbabwe's central bank introduced higher denomination banknotes and increased daily cash withdrawal limits on Wednesday, barely a month after a similar move to end a severe cash shortage due to inflation.

Following are some major events in Zimbabwe's recent political crisis:

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

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

2000 - Mugabe gets taste of electoral defeat when voters back the MDC and turn down a proposed constitutional amendment which would have given the president more power.

-- Mugabe's ruling ZANU-PF goes on to win a parliamentary poll amid charges of fraud and vote-rigging by the opposition.

-- Thousands of so-called independence war veterans, backed by the government, seize white-owned farms, saying the land was illegally seized 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 six-year term in election pitting him against Tsvangirai. Observers condemn poll as flawed and unfair. Commonwealth suspends Zimbabwe.

2003 - The IMF begins steps to expel Zimbabwe from the fund over dues unpaid since 2001. Commonwealth agrees at summit in Abuja to continue suspension, leading Mugabe to pull Zimbabwe out of the organization.

2004 - The EU renews sanctions against Mugabe and his inner circle in February. In October the High Court acquits Tsvangirai of plotting to assassinate Mugabe and seize power, a ruling condemned by the government. Remaining charges are dropped in August 2005.

2005 - The ruling ZANU-PF wins the March parliamentary election, giving it the majority it needs to change the constitution.

-- In May-July some 700,000 people lose their homes or livelihoods after a highly criticized government blitz on urban slums.

2006 - Zimbabwe's annual inflation rises above 1,000 percent in April.

2007 - Tsvangirai badly beaten in March after he attempts to attend a banned protest rally, spurring international condemnation of Mugabe's government.

-- Central bank raises its main lending rate to 800 percent from 650 percent on October 1 to fight inflation. The bank says it will launch a new currency soon to try to curtail a thriving foreign exchange black-market.