Key developments in the Gulf state of Bahrain:

FEBRUARY

- 14: Demonstrations in several Shia-majority villages.

- 15: King Hamad goes on television to apologise for the deaths of two Shia demonstrators.

- 16: Thousands gather in Pearl Square in central Manama, which becomes the focus of the protests.

- 17: Four demonstrators die in an overnight police attack on Pearl Square. The main opposition movement, Al-Wefaq, withdraws from parliament.

- 18: Dozens wounded when soldiers open fire on demonstrators in Manama. Crown Prince Sheikh Salman promises to start a national dialogue.

- 21: The Bahrain Formula One Grand Prix, due to be staged in March, is cancelled.

- 22: King Hamad orders the release of Shia prisoners. Tens of thousands of opposition supporters pour into the streets of Manama, in the largest rally yet.

- 26: King Hamad makes social concessions, notably sacking his ministers for housing, health and water and electricity. The opposition says the measures are not enough.

MARCH

- 2: A counter-demonstration attracts 300,000 people in support of the royal family.

- 12: US Defence Secretary Robert Gates visits the kingdom and calls for major reforms.

- 13: Dozens of protesters are hospitalised after security forces fire tear gas in Manama.

- 14: Armoured troops enter Bahrain from neighbouring Saudi Arabia. Riyadh says it has responded to a call for help from Manama as Saudi and Emirati forces from the Gulf countries' joint Peninsula Shield Force cross the causeway separating the two countries.

- 15: Medical sources say at least 200 people have been shot during unrest in a village south of the capital. A Shia protester and a member of the security forces are reported killed elsewhere. The government announces a three-month state of emergency, a measure condemned by nearby Iran. In reaction, Bahrain withdraws its ambassador from Tehran.

- 16: Police backed by tanks and helicopters mount a massive operation to clear Pearl Square of protesters. The opposition says three demonstrators are killed, and the government says two police die in hit-and-run attacks by protesters in cars. Troops enter the capital's nearby financial centre to remove protesters. Iranian President Mahmoud Ahmadinejad denounces the repression, and accuses Bahrain of acting to support the United States and Israel. The total death toll since the start of the protests is estimated at 16.