The conflict between Israel and Hamas is the most intense fighting in Gaza since the Arab Spring uprisings began to change the dynamics of regional politics in the Middle East. Here's a list of some of the regional and international forces at play.
Middle East experts say the outbreak of violence between Israel and Hamas is the result of events that have reshaped the power structures within Hamas and its relations with regional forces -- including Syria, Iran, Egypt, and Israel.
ISRAEL AND PRIME MINISTER BENJAMIN NETANYAHU'S GOVERNMENT
The declared goal of Israel's air and naval strikes on Gaza is to stop the Palestinian Islamist group Hamas from launching rockets that have targeted southern Israel for years. Israel considers its military campaign to be a legitimate response to almost daily rocket attacks from Hamas-ruled Gaza -- where Israel and Palestinian militants fought a three-week conflict in late 2008 and early 2009.
The Israeli ambassador to the United States, Michael Oren, says that Israel has "exhibited superhuman restraint" since 2009 by not responding to more than 2,500 rocket attacks from Gaza. Israel -- along with the United States and the European Union -- has designated Hamas as a terrorist organization.
According to Shin Bet, the Israeli Security Agency, Gaza militants fired more than 1,500 rockets at Israel during 2012 before Israel responded on November 14 by killing Hamas military chief Ahmed Jabari in a targeted air strike. Since then, according to the Israel Defense Forces, some 850 rockets have been fired from Gaza at Israel -- with more than 300 penetrating Israel's antimissile systems.
Prime Minister Benjamin Netanyahu has argued that "if Israel were to put down its arms, there would be no more Israel. If the Arabs were to put down their arms, there would be no more war."
PALESTINIAN FACTIONS: HAMAS AND FATAH
Hamas is seen by its supporters as a legitimate resistance movement against the Israeli occupation of Palestinian territories in the West Bank and Gaza.
Created in 1987 after the start of the first intifada against the Israeli occupation, Hamas is -- according to its charter -- committed to the destruction of Israel. Hamas officials say they can neither recognize nor accept the existence of Israel until Israel recognizes their existence.
Hamas won the Palestinian parliamentary elections of 2006. But the victory sparked tensions with the rival Fatah faction -- the secular nationalist party of Palestinian President Mahmud Abbas that controls the West Bank. In fact, the two factions have been politically and geographically divided since the tensions escalated into violence in Gaza in June 2007.
The politburo of Hamas, based almost entirely in nearby Arab countries, traditionally had been more militant than the movement's domestic political leadership in Gaza -- that is, until the Arab Spring changed the dynamics of politics in the Middle East. Since then, Hamas leaders in Gaza have increasingly argued that they are the movement's top leadership.
SYRIA AND PRESIDENT BASHAR AL-ASSAD'S REGIME
Hussein Ibish, a senior fellow at the American Task Force on Palestine, points to the Syrian uprising as a key regional development affecting the foreign alliances of Hamas. The Hamas politburo had close relations with Iran and Syria through its headquarters in Damascus. But writing recently in Foreign Policy, Ibish noted that relations between Hamas and the Syrian government "completely collapsed" after Hamas registered opposition to the crackdown on dissent by President Bashar al-Assad's regime. As a result, the Hamas politburo was forced to abandon its Damascus headquarters and its members scattered throughout the Arab world.
IRAN AND PRESIDENT MAHMOUD AHMADINEJAD
Iran -- a key ally of Assad's regime in Syria -- also has been a key supporter of Hamas for years. Iranian President Mahmud Ahmadinejad in 2010 called Hamas the true representative of the Palestinian people. That angered the rival Palestinian faction Fatah, which accused Iran of trying to divide the Palestinian people and foment strife. Meanwhile, Palestinian President Abbas said before the Arab Spring began that Hamas was being funded mainly by Iran. Ibish says that the closure of the Hamas politburo headquarters in Damascus has created "enormous strains with Iran, which is apparently supplying much less funding and material to Hamas than in the past." Nevertheless, Tehran continues to issue statements in support of Hamas. In September, Ahmadinejad said that Israel was an "occupier" without roots in the Middle East and would be "eliminated." Previously, Ahmadinejad called Israel a "tumor" and said it should be wiped off the map.
LEBANON AND HEZBOLLAH
In Lebanon, Hezbollah leader Hassan Nasrallah has called on Arab countries to show support for Hamas and to open their borders for Palestinian refugees trying to flee the fighting. Nasrallah has criticized Arab leaders for failing to provide more support to Palestinians in Gaza. He also said that Israel is taking advantage of the Syrian civil war to wage an assault on Gaza. He said Hezbollah was able to provide support to Gaza through Syria in the 2008-09 Israel-Gaza conflict. But that is impossible now because of the ongoing conflict in Syria, he said.
EGYPT AND PRESIDENT MOHAMED MORSI
The Gaza conflict puts Egypt's newly elected Islamist president, Mohamed Morsi, in a challenging position. Egypt needs to keep good relations with the United States to secure millions of dollars in military aid, as well as economic support from Saudi Arabia and institutions like the World Bank. But Morsi, a Sunni Muslim, also faces strong calls from the Egyptian people to intervene in the Gaza conflict. Morsi came to power through elections after the 2011 uprising that ousted longtime ruler Hosni Mubarak -- one of Israel's few allies in the Middle East. Under Morsi, Egypt has pushed to secure a truce between Israelis and Palestinians.
Qatar is an ally of the United States and previously maintained some ties with Israel. But relations have deteriorated in recent years with Qatar supporting Hamas in its conflict with Israel. In October, the emir of Qatar -- Sheik Hamad bin Khalifa al-Thani -- became the first head of state to visit Gaza since Hamas took over the territory's administration in 2007. As Israel's offensive against Gaza has intensified, Qatar has called for Israel to be "punished." Along with Egypt, Qatar has been a driving force within the Arab League that is pushing for a truce.
THE ARAB LEAGUE
The Arab League -- led by Secretary-General Nabil al-Arabi -- has backed Egypt's efforts to establish a truce between Israel and Hamas. Arabi also has condemned "Israel's aggression" against Palestinians and pledged to "confront this aggression and break the siege," bringing an end to an Israeli economic blockade imposed on Gaza since 2007.
Turkish Prime Minister Recep Tayyip Erdogan also has called for an immediate truce between the Palestinians and Israel. He said that Israel's economic embargo against Gaza should be "abolished in a gradual way" and that peace talks should be launched within 90 days. On November 19, he issued sharper comments, calling Israel a "terrorist state" becaus of its Gaza assault.
THE UNITED STATES
The United States has blamed Hamas for the outbreak of violence in Gaza, while also saying it regrets the death and injury of innocent Israeli and Palestinian civilians. President Obama said on November 18 that Washington fully supports Israel's right to defend itself against rocket attacks from Gaza, but it is "preferable" for the Gaza crisis to be resolved without "ramping up" Israeli military activity. Obama said that a series of rocket attacks on Israeli territory by Hamas was the "precipitating event" of the crisis.
THE U.N. SECURITY COUNCIL
The United Nations Security Council has called for a halt to violence between Hamas and Israel but has taken no action to date. While Arab envoys have called on the Security Council to condemn Israel's attacks, U.S. Ambassador to the U.S. Susan Rice has said, "There is no justification for the violence that Hamas and other terrorist organizations are employing against the people of Israel." U.N. Secretary-General Ban Ki-moon has issued statements expressing concern about "the worrisome escalation of violence in southern Israel and Gaza and the need to prevent any further deterioration." He also has held talks about the violence with Israeli Prime Minister Netanyahu and Egyptian President Morsi.