(Reuters) - Here is a timeline of events in Syria since protests started in March.
March 16 - Security forces break up a silent gathering in Marjeh square in Damascus of about 150 protesters holding up pictures of imprisoned relatives and friends. Witnesses say at least 30 people are arrested.
March 18 - Security forces kill three protesters in southern Deraa city, residents say.
March 20 - Crowds set fire to the headquarters of the ruling Baath Party in Deraa, residents say.
March 23 - Syrian forces kill six people in an attack on protesters in the Omari mosque in Deraa and later open fire on hundreds of youths marching in solidarity.
-- An official statement says President Bashar al-Assad has sacked Deraa regional governor Faisal Kalthoum.
March 24 - Assad orders the formation of a committee to raise living standards and study lifting the law covering emergency rule, in place for 48 years.
March 27 - Assad sends troops to Latakia.
March 29 - Government resigns. Assad appoints Naji al-Otari, head of the government that stepped down, as caretaker prime minister.
March 30 - Assad says a minority of people tried to “spark chaos” in Deraa. Security forces have been told not to harm anyone during the protests, he tells parliament in his first public comments since protests erupted.
March 31 - Assad sets up a committee to look into replacing the emergency law with anti-terrorism legislation.
April 3 - Thousands call for freedom at funeral of eight protesters. Assad tells former agriculture minister to form new government.
April 8 - Protests erupt across Syria. Sources say 22 people are killed in Deraa. In the east, thousands of ethnic Kurds demonstrate for reform.
April 9 - A Syrian rights group accuses security forces of committing a crime against humanity by killing at least 37 people during Friday’s nationwide demonstrations.
April 14 - Assad unveils a new cabinet and orders the release of detainees arrested during a month of protests.
April 19 - Government passes bill lifting emergency rule.
April 21 - Assad ratifies the law ending emergency rule.
April 22 - Security forces and gunmen loyal to Assad kill at least 100 protesters, a rights group says.
April 23 - Security forces fire on mourners calling for the end of Assad’s rule at mass funerals of pro-democracy protesters shot a day earlier, killing at least 12 people.
April 25 - Troops and tanks pour into Deraa, killing more than 20 in effort to crush resistance.
April 29 - The United States imposes new sanctions on figures including Assad’s cousin Atif Najib and his brother Maher, who commands the army division which stormed into Deraa.
-- Rights group Sawasiah says 62 killed during protests in Deraa, Latakia, Homs and the town of Qadam, near Damascus.
-- In Rastan security forces kill 17 demonstrators, residents say. Some 50 members of the ruling Baath Party resign, according to a human rights activist.
May 3 - Security forces take control of the coastal city of Banias, where demonstrators have challenged Assad.
-- Hundreds of Syrians including activists and community leaders, have been charged with “maligning the prestige of the state,” a Syrian rights group says.
May 9 - Assad sends tanks to Homs, Syria’s third city. May 10 - EU sanctions come into effect. The EU had agreed to impose travel restrictions and asset freezes on up to 13 Syrian officials for their part in the crackdown.
May 12 - Tanks advance in the southern towns of Dael, Tafas, Jassem and al-Harra before Friday, the Muslim day of prayer.
May 17 - Security forces kill at least 27 civilians in a three-day tank-backed attack on the border town of Tel Kelakh to subdue protesters, rights lawyer Razan Zaitouna says.
May 20 - Security forces shoot dead at least 44 civilians in attacks on protests that erupted across Syria, the Syrian National Organisation for Human Rights says.
May 23 - The EU adds Assad and nine other senior members of the government to a list of those banned from travelling to the EU and subject to asset freezes.
May 24 - Syrian troops and security forces have killed at least 1,100 civilians in their two-month campaign to crush pro-democracy protests, rights group Sawasiah says.
Writing by David Cutler, London Editorial Reference Unit