Here is some background about the on-going civil war in Syria. Since the war began in 2011, more than 100,000 Syrians have been killed, according to the United Nations.
Facts: Bashar al-Assad has ruled Syria as president since July 2000. His father, Hafez al-Assad, ruled Syria from 1970-2000.
The ongoing violence against civilians has been condemned by the Arab League, the European Union, the United States, and other countries.
Timeline: March 2011 - Violence flares in Daraa after a group of teens and children are arrested for writing political graffiti. Dozens of people are killed when security forces crack down on demonstrations.
March 24, 2011 - In response to continuing protests, the Syrian government announces several plans to appease citizens. State employees will receive an immediate salary increase. The government also plans to study lifting Syria's long standing emergency law and the licensing of new political parties.
March 30, 2011 - President al-Assad addresses the nation in a 45-minute televised speech. He acknowledges that the government has not met the people's needs but he does not offer any concrete changes. The state of emergency remains in effect.
April 21, 2011 - Al-Assad lifts the country's 48-year-old state of emergency. He also abolishes the Higher State Security Court and issues a decree "regulating the right to peaceful protest, as one of the basic human rights guaranteed by the Syrian Constitution."
May 18, 2011 - The U.S. imposes sanctions against Syrian President Bashar al-Assad and six other senior Syrian officials. The Treasury Department details the sanctions by saying, "As a result of this action, any property in the United States or in the possession or control of U.S. persons in which the individuals listed in the Annex have an interest is blocked, and U.S. persons are generally prohibited from engaging in transactions with them."
August 18, 2011 - The U.S. imposes new economic sanctions on Syria, freezing Syrian government assets in the U.S., barring Americans from making new investments in the country and prohibiting any U.S. transactions relating to Syrian petroleum products, among other things.
September 2, 2011 - The European Union bans the import of Syrian oil.
September 23, 2011 - The European Union imposes additional sanctions against Syria, due to "the continuing brutal campaign" by the government against its own people.
October 2, 2011 - A new alignment of Syrian opposition groups establishes the Syrian National Council, a framework through which to end President al-Assad's government and establish a democratic system.
October 4, 2011 - Russia and China veto a U.N. Security Council resolution that would call for an immediate halt to the crackdown in Syria against opponents of President Bashar al-Assad. Nine of the 15-member council countries, including the United States, voted in favor of adopting the resolution.
November 12, 2011 - The Arab League suspends Syria's membership, effective November 16, 2011.
November 27, 2011 - Foreign ministers from 19 Arab League countries vote to impose economic sanctions against the Syrian regime for its part in a bloody crackdown on civilian demonstrators.
November 30, 2011 - Turkey announces a series of measures, including financial sanctions, against Syria.
December 19, 2011 - Syria signs an Arab League proposal aimed at ending violence between government forces and protesters.
January 28, 2012 - The Arab League suspends its mission in Syria as violence there continues.
February 2, 2012 - A U.N. Security Council meeting ends with no agreement on a draft resolution intended to pressure Syria to end its months-long crackdown on anti-government demonstrators.
February 4, 2012 - A U.N. Security Council resolution condemning action against Syria is not adopted after Russia and China vote against it.
February 6, 2012 - The U.S. closes its embassy in Damascus and recalls its diplomats.
February 7, 2012 - The Gulf Cooperation Council announces its member states are pulling their ambassadors from Damascus and expelling the Syrian ambassadors in their countries.
February 16, 2012 - The United Nations General Assembly passes a nonbinding resolution endorsing the Arab League plan for Syrian president Bashar al-Assad to step down. The vote was 137 in favor and 12 against, with 17 abstentions.
February 26, 2012 - Syrians vote on the constitutional referendum in polling centers across the country. Almost 90% of voters approve the changes to the constitution.
March 13, 2012 - Kofi Annan, the U.N. special envoy to Syria, meets in Turkey with government officials and Syrian opposition members. He visits Syria over the weekend where he calls for a cease-fire, the release of detainees and allowing unfettered access to relief agencies to deliver much needed aid.
March 15, 2012 - The Gulf Cooperation Council announces that the six member countries will close their Syrian embassies and calls on the international community "to stop what is going on in Syria." The council members include the United Arab Emirates, Bahrain, Saudi Arabia, Oman, Qatar and Kuwait.
March 21, 2012 - After a year of fighting, the U.N. believes more than 8,000 people have died. Opposition activists claim the number to be higher than 10,000 and most of the dead are civilians.
March 27, 2012 - The Syrian government accepts U.N. envoy Kofi Annan's plan to end violence. The proposal seeks to stop the violence, give access to humanitarian agencies, release detainees, and start a political dialogue to address the concerns of the Syrian people.
April 1, 2012 - At a conference in Istanbul, Turkey, the international group Friends of the Syrian People formally recognizes the Syrian National Council as a legitimate representative of the Syrian people.
June 10, 2012 - Abdul Basit Sieda, a Syrian native now living in Sweden, is now Syria's National Council leader.
June 13, 2012 - The U.N. Security Council has authorized up to 300 unarmed military observers for a 90-day mission in Syria. The monitors are tasked with observing a cease-fire that was supposed to go into effect April 12, though both the Syrian regime and opposition have reported at least hundreds of killings since then. In addition, observers are tasked with supporting the implementation of Annan's peace plan, which also calls for access for humanitarian groups, the release of arbitrarily arrested detainees and the start of a political dialogue.
June 16, 2012 - The U.N. suspends its monitoring mission due to intensifying violence.
July 23, 2012 - The Syrian Foreign Ministry spokesman, Jihad Makdissi, threatens to use chemical and biological weapons against outside forces, "No chemical or biological weapons will ever be used, ... unless Syria is exposed to external aggression."
July 30, 2012 - The Syrian Charge d'Affaires in London, Khaled al-Ayoubi, resigns stating he is "no longer willing to represent a regime that has committed such violent and oppressive acts against its own people."
August 2, 2012 - U.N. Secretary General Ban Ki-moon announces that Special Envoy for Syria Kofi Annan will not renew his mandate when it expires at the end of August.
August 6, 2012 - Syrian Prime Minister Riyad al-Hijab's resignation from office and defection from Assad's regime is read on Al Jazeera by his spokesman Muhammad el-Etri. Hijab and his family are said to have left Syria overnight arriving in Jordan. Hijab is the highest-profile official to defect.
August 9, 2012 - Syrian television reports that President al-Assad has appointed Health Minister Wael al-Halki as the new prime minister.
October 3, 2012 - Five people are killed by Syrian shelling in the Turkish border town of Akcakale. In response, Turkey fires on Syrian targets and its parliament authorizes a resolution giving the government permission to deploy its soldiers to foreign countries.
November 11, 2012 - Israel fires warning shots toward Syria after a mortar shell hits an Israeli military post. It is the first time Israel has fired on Syria across the Golan Heights since the 1973 Yom Kippur War.
November 11, 2012 - Syrian opposition factions formally agree to unite as the National Coalition for Syrian Revolutionary and Opposition Forces.