The following is a timeline of key events in Thailand's political crisis since demonstrations aimed at toppling Prime Minister Yingluck Shinawatra's government began more than three months ago:

October 31: Protests break out against an amnesty bill which critics said was aimed at allowing former premier Thaksin Shinawatra -- Yingluck's brother -- to return without going to jail for a corruption conviction.

November 1: The lower house of parliament, which is dominated by the ruling party, votes in favour of the bill.

November 11: Amid growing outrage on the streets, the upper house overwhelmingly rejects the legislation.

November 25: Opposition supporters march on state buildings, occupying the finance ministry.

November 26: Protesters besiege several ministries while police issue an arrest warrant for rally leader Suthep Thaugsuban.

November 30: Opposition demonstrators attack a bus carrying government supporters. Several people are killed and dozens wounded in street violence.

December 1: Police use water cannon and tear gas on protesters who storm the government and police headquarters.

December 8: Opposition lawmakers resign en masse from parliament.

December 9: Yingluck calls early elections. Opposition later announces boycott.

December 22: Protesters stage massive anti-government rally in Bangkok. Police say 150,000 people attend but organisers insist the number is much higher.

December 26: The government rejects a call from the Election Commission to postpone the ballot after violent clashes

December 27: The army chief refuses to rule out a coup, saying "anything can happen".

December 28: An unknown gunman kills one protester and wounds several others -- the start of a series of drive-by shootings targeting demonstrators.

January 13: Tens of thousands of protesters occupy major streets in the capital in an attempt to "shut down" Bangkok.

January 16: Anti-corruption authorities probe possible negligence of duty by Yingluck over a controversial rice subsidy scheme.

January 17: A grenade wounds dozens at an opposition march, the first of several blasts targeting the rallies. One of the injured later dies.

January 21: Government declares a 60-day state of emergency in Bangkok and surrounding areas.

January 26: A protest leader is shot dead while giving a speech, as fellow demonstrators disrupt advance voting for the election.

February 1: A daylight gun battle shakes Bangkok as pro- and anti-government protesters clash.

February 2: Demonstrators prevent 10,000 polling stations from opening for the election, affecting several million people.

February 11: The election commission says election re-runs will be held on April 27 in constituencies where voting was obstructed.

February 12: The Constitutional Court rejects a legal bid by the opposition to annul the polls.

February 14: Thousands of riot police are deployed in Bangkok to reclaim government buildings surrounded by demonstrators.