Syria: How The Crisis Has Developed
Updated: 2:33pm UK, Saturday 14 September 2013
:: March 2011 - Protesters stage demonstrations in Damascus and security forces in Daraa shoot dead several campaigners, leading to unrest and violence.
:: May - The Syrian military deploys tanks in a bid to quash demonstrations.
:: July 19 - The UK freezes £100m of Syrian assets.
:: August 18 - US President Barack Obama calls on Bashar al Assad to step down. The US freezes all assets of the Syrian government.
:: November 16 - The Free Syrian Army attacks a military base near Damascus.
:: February 4, 2012 - A UN Security Council resolution on Syria is rejected for a second time by Russia and China.
:: March 1 - Government troops seize the Baba Amr district of Homs after an intense battle lasting for several weeks.
:: April 12 - A UN-brokered ceasefire comes into force after fierce fighting in the country.
:: May 23 - Dozens of people, many of them women and children, die in Houla, near Homs. Foreign Secretary William Hague says they were "massacred at the hands of Syrian forces". The UN later accuses the Syrian military of committing war crimes.
:: August - Barack Obama says the use of chemical weapons against civilians would represent the crossing of a "red line".
:: March 6, 2013 - Foreign Secretary William Hague says Britain will provide opposition forces with "non-lethal equipment for the protection of civilians".
:: April-May - Britain says there is credible evidence to suggest Syrian forces have used chemical weapons in Adra, Darayya and Saraqiq and calls for an investigation by the UN.
:: April 29 - Syrian prime minister Wael Nader al Halqi survives an assassination attempt as a car bomb explodes in Damascus.
:: May 14 - Footage of a Syrian rebel commander apparently cutting out a soldier's heart is condemned by the country's National Coalition.
:: June 6 - Syrian forces, backed by Hizbollah fighters, recapture the strategic border town of Qusair.
:: June 6 - Human Rights Watch releases footage which it claims shows Syrian troops shelling school buildings.
:: July 25 - The UN says the number of people killed in the civil war has reached 100,000.
:: August 21 - An alleged chemical attack in Damascus kills 1,300 people, according to the opposition. Doctors Without Borders says 335 people died from "neurotoxic" symptoms.
:: August 25 - Foreign Secretary William Hague says a chemical attack by the Syrian government is the only "plausible explanation" for the deaths.
:: August 26 - UN inspectors brave sniper fire to gather "valuable" evidence from one site of the alleged chemical attack, as the US Secretary of State John Kerry says the Assad regime would face action over the "moral obscenity".
:: August 27 - The UK recalls Parliament to hold a vote on August 29 on the use of chemical weapons in Syria. David Cameron and Barack Obama agree there is "no doubt" the Assad regime is responsible for the alleged attack.
:: August 28 - Britain tables a draft UN resolution condemning the alleged attack and "authorising all necessary measures".
:: August 29 - David Cameron is forced to rule out military action after narrowly losing a Commons vote on the principle of intervention.
:: August 31 - President Obama says the US "should take military action" in Syria but confirms he will seek authorisation from Congress before launching any strikes against the Assad regime. He says the US is "prepared to strike whenever we choose".
:: September 2 - a French intelligence reports claims the Assad regime was responsible for a "massive and coordinated" chemical attack in Damascus.
:: September 3 - Israel says it has carried out a joint missile test with the US in the Mediterranean.
:: September 4 - The Senate Foreign Relations Committee approve a draft US resolution authorising the use of military force in Syria. Meanwhile, MPs in France debate whether to join any possible military intervention, although they do not vote on the subject.
:: September 5 - World leaders meet at the G20 summit in Russia, with the crisis in Syria high on the agenda.
:: September 6 - Britain pledges £52m in aid to Syria, as David Cameron hits back at a reported jibe from Russia that Britain is a "small island".
:: September 8 - The RAF sends up two Typhoon jets in Cyprus as warplanes, thought to have come from Syria, enter international airspace. Meanwhile John Kerry says more nations than his country can use are prepared to join military action against Syria.
:: September 9 - Russia urges Syrian President Bashar al Assad to hand over his chemical weapons to avert a US-led military strike on Damascus.
:: September 10 - President Barack Obama delays a Congress vote on air strikes as Russia gives the US its plan for putting Syria's chemical weapons under international contral.
:: September 11 - A UN report confirms at least eight massacres were carried by the Assad regime and one by rebels over the past 18 months.
:: September 12 - Syria formally applies to join the Chemical Weapons Convention. Russia and US hold two days of talks on the issue.
:: September 14 - The US and Russia agree on a giving Syria a deadline of one week to produce a list of chemical weapons they possess.