The government declared a state of emergency early on Thursday morning, aimed at protesters who have demanded the removal of Prime Minister Prayut Chan-o-cha and called for reform of the monarchy.
Below is a timeline of events since Prayut was appointed prime minister after an election in March 2019. He rejects accusations the electoral laws were fixed in his favour.
June 9, 2019 - The King endorses Prayut as prime minister, keeping him in the post he first took in a 2014 coup.
Nov 20 - Constitutional court disqualifies vocal opposition figure Thanathorn Juangroongruangkit as a member of parliament, saying he violated electoral law. He disputes the ruling.
Dec 14 - Several thousand protesters demonstrate in Bangkok to protest against Thanathorn's disqualification and the moves to ban his Future Forward party.
Feb 21, 2020 - Constitutional court bans Future Forward. The next day, hundreds of people join a protest against the decision.
March 26 - Authorities impose a state of emergency to stop the spread of the coronavirus, limiting gatherings and travel.
July 18 - The Free Youth group draws about 2,500 to a protest in Bangkok and makes three demands: dissolve parliament, amend the constitution and stop harassing critics.
Aug 3 - Human rights lawyer Arnon Nampa makes an unprecedented call for reform of the monarchy at a protest with a Harry Potter theme.
Aug. 10 - Students at Thammasat University list 10 demands for reforming the monarchy, including abolition of lese majeste law against criticising the monarchy.
Aug 16 - More than 10,000 people protest at Bangkok's Democracy Monument.
Sept 19 - Tens of thousands protest in the biggest demonstration since the 2014 coup, cheering calls for reforms to the monarchy as well as for the removal of Prayut.
Sept 20 - Protesters install a plaque near the Grand Palace in Bangkok with the message that Thailand belongs to the people and not to the monarch. It was removed the next day.
Sept 24 - Parliament votes to delay considering changes to the constitution.
Oct 13 - Protesters scuffle with police and chant at the King's passing motorcade to demand the release of 21 arrested protesters.
Oct 14 - Tens of thousands of protesters march to Prayut's office, Government House, and set up camp to demand his removal. Police fend off jeering protesters as the Queen's convoy passes close to them.
Oct 15 - Government orders emergency measures that include bans on gatherings of five or more people and on news that could affect national security.
Police clear protesters from Government House and arrest several protest leaders among more than 20 people held.