Syria's long-time ally Russia has blocked all draft UN Security Council resolutions condemning the brutal crackdown by President Bashar Al-Assad's regime on an 11-month pro-democracy protest movement, most recently at the weekend.
Here are key dates in their relationship.
- October 8, 1980: The Soviet head of state Leonid Brezhnev and Syria's leader Hafez al-Assad sign in Moscow a treaty of friendship and cooperation which establishes special strategic links.
- April 24, 1987: Soviet leader Mikhail Gorbachev assures Assad in Moscow that the Soviet Union will continue to provide Syria with economic and military aid. The previous bilateral summit in 1985 had been marked by differences over the Palestinian problem and the Iran-Iraq war.
- 1990: Before the Soviet Union dissolves, Syria reinforces links with the United States, boosting its position by joining the international coalition against Iraqi leader Saddam Hussein during the Gulf war.
- July 5-6, 1999: Assad visits Russia for the first time since the collapse of the Soviet Union. Assad and Russian leader Boris Yeltsin speak out against "any dictatorship of one or several countries" in the world's affairs.
- January 24-27, 2005: Bashar al-Assad, who succeeded his father in 2000, meets Russian President Vladmir Putin in Moscow. Both countries say they are determined to renew Soviet-era privileged links and Russia agrees to annul 73 percent of Syria's Soviet-era debt.
- August 21, 2008: Assad backs Russian military operation in Georgia during talks with his Russian counterpart Dmitry Medvedev in Sochi, southern Russia, and discusses purchasing new kinds of Russian arms.
- September 12, 2008: A delegation from the Syrian Navy visits Russia. Moscow and Damascus call for military cooperation between their fleets, notably the development of infrastructure in the port of Tartus in northwestern Syria.
- May 10-11, 2010: Medvedev visits Damascus, becoming the first Russian president to do so, and vows to help Syria build its oil and gas infrastructure as well as developing a nuclear energy plant.
- August 17, 2011: Russia continues to deliver arms to Syria, in spite of international pressure.
- October 4, 2011: Russia and China veto a UN resolution threatening Damascus with "targeted measures".
- January 8, 2012: A large Russian naval flotilla led by an aircraft carrier docks in Tartus, in what Syrian state media hails as a show of solidarity by Moscow.
- January 14, 2012: A Russian ship thought to be carrying munitions arrives in Tartus.
- January 23: Syria has signed a $550 million (425 million euro) contract to purchase 36 Yak-130 advanced training fighter planes from Russia, the Kommersant business daily reports.
- February 4: Russia and China veto a UN Security Council resolution condemning the Syrian government's deadly crackdown on protests for the second time, prompting indignation in the Arab world, in the West and in the Syrian opposition.
- February 6: Russian Foreign Minister Sergei Lavrov condemns as "hysterical" the West's angry reaction to the Russian veto.
