Here is a look at how neighboring states are being affected by Syria's bloodletting:
Turkey has struck the Syrian military repeatedly in response to shelling and mortar rounds from Syria since Oct. 3, when shells from Syria struck the Turkish village of Akcakale, killing two women and three children. The incident prompted NATO to convene an emergency meeting and Turkey sent tanks and anti-aircraft batteries to the area. Turkey's military has also scrambled fighter jets after Syrian helicopters flew close to the border. There are about 120,000 Syrian refugees sheltering in Turkish camps, with up to 70,000 more living in Turkey outside the camps. Thousands more wait at the border, held up as Turkey struggles to cope with the influx. Turkey also hosts much of the opposition and rebel leadership. Turkey has called for a buffer zone in Syria where the opposition and civilians would be protected, a step that would likely require international enforcement of a no-fly zone. Russia and China have blocked robust moves against the Syrian regime at the U.N. Security Council, and the United States has been reluctant to use its military in another Mideast conflict.
Israel on Monday became the second country to strike the Syrian military, after Turkey. An Israeli tank hit a Syrian armored vehicle after shells from fighting in Syria exploded in Israel-controlled Golan Heights. A day earlier, Israel fired a warning shot near a group of Syrian fighters. Syrian shells have exploded inside the Golan several times in recent weeks damaging apple orchards, sparking fires and spreading panic but causing no injuries. In early November, three Syrian tanks entered the Golan demilitarized zone, and in a separate incident an Israeli patrol vehicle was peppered with bullets fired from Syria; no one was hurt in the incident and the Israeli military deemed it accidental. There is concern in Israel that Assad may try to spark a conflict with Israel, opening up the potential for attacks by Lebanon's militant Hezbollah and Hamas in the Gaza Strip. Israel has also warned that Syria's chemical weapons could be turned on the Jewish state. Still, while no friend of Assad, Israel is also worried that if he is toppled, Syria could fall into the hands of Islamic extremists or descend into sectarian warfare.
Mortars and shells from the Syrian side regularly crash in Lebanon, causing several casualties, though Lebanese forces have never fired back. More dangerously, Syria's conflict has heightened deep rivalries and sectarian tensions in its smaller neighbor. Lebanon is divided between pro-Assad and anti-Assad factions, a legacy of the nearly three decades when Damascus all but ruled Lebanon, until 2005. Assad's ally, the Hezbollah militia is Lebanon's strongest political and military movement. On Oct. 19, a car bomb assassinated Lebanon's top intelligence chief, Wissam al-Hassan. Many in Lebanon blamed Syria and Hezbollah for the assassination. The northern Lebanese city of Tripoli has seen repeated clashes between Sunni Muslims and Alawites - the Shiite offshoot sect to which Assad belongs. Battles in the city in May and August killed at least 23 people total and wounded dozens. The kidnapping of Lebanese Shiites in Syria by rebels has also had repercussions in Lebanon. In May, Shiites blocked roads and burned tires in protest over the abductions, and later in the summer a powerful Shiite clan took 20 Syrians and a Turk in Lebanon captive in retaliation, all of whom have since been released. Lebanon also shelters about 100,000 Syrian refugees.