Hamas has grown to become a powerful force in Palestinian politics [GALLO/GETTY]

Hamas, the Palestinian political movement that controls Gaza, rose to international prominence following its armed campaign against Israel during the second intifada, or uprising, which began in 2000.

The organisation, founded in 1987 as an offshoot of the pan-Arab Muslim Brotherhood movement, had already achieved widespread popularity in the Palestinian territories for its resistance to the Israeli military occupation and for its social programmes.

The pinnacle of that popularity came in January 2006, when the movement won a stunning victory in the Palestinian parliamentary elections.

But the years since then, marked by a crippling international embargo, internal conflict with rivals Fatah, and Israeli attacks on its members, have proved a testing time for the organisation.

And with Israel launching the bloodiest raids into Gaza in decades, the group faces an uncertain future.

Hamas, which stands for Islamic Resistance Movement, and also means 'zeal' in Arabic, was founded at the beginning of the first intifada by the religious leader Sheikh Ahmed Yassin.

The movement's main goal is to end the Israeli military occupation of the West Bank and Gaza but its charter states its long term aim is the creation a Palestinian state on what was called Palestine before the creation of Israel in 1948.

It built its popularity on providing support to impoverished Palestinians by constructing schools, hospitals and religious centres.

Unlike many other Palestinian political movements, Hamas has rejected membership of the Palestinian Liberation Organisation, calling for its restructuring, and has opposed signing peace agreements with Israel, although it has offered Israel a number of fixed-term truces.

Leadership

Israel has assassinated several of the group's prominent leaders, most notably Sheikh Yassin in 2004, and Abdul Aziz al-Rantissi, the movement's leader in its stronghold of Gaza, only a few weeks later. 

Sheikh Ahmed Yassin, who founded Hamas, was assassinated by Israel in 2004 [AP]

Ismail Haniya, the movement's senior figure in Gaza and the deposed prime minister, was a close associate of Sheikh Yassin and once ran his office.

Khalid Meshaal, currently exiled in Syria, has also been a senior political leader of Hamas, since 1995, following the arrest and jailing of Mussa Abu Marzouq, the former Hamas political leader.

Meshaal had led the Kuwait chapter of the organisation, but left the country when Iraq invaded in 1990.

He moved to the Jordanian capital, Amman, where he became head of Hamas and was subject to a failed assassination attempt by Israel.

Hamas is reported to be funded by donations from Palestinian supporters both inside and outside the territories, other Arabs and also the Iranian government.

Its military wing, the Ezzedine al- Qassam Brigades, which is believed to have several thousand members, has also carried out some of the bloodiest attacks in the Israeli-Palestinian conflict.

The Brigades, along with other Palestinian armed groups, have carried out sustained rocket attacks on Israeli towns in the south of the country, often in response to Israeli strikes on Gaza.

Second intifada

Hamas bolstered its reputation in the 1990s by its efforts to keep order in the often troubled Gaza Strip - something that won it the respect of those who would not normally ally itself with the movement. 

Israel has blamed Hamas for carrying out rocket attacks from Gaza [AFP]

The movement took a tough stance on corruption - a charge often levelled at its Fatah rivals.

But it also became known for its suicide attacks on Israel, the first of which was carried out in 1994.

When peace talks between Israel and the Palestinians broke down once again in 2000, Hamas joined other Palestinian political and armed groups in the second intifada against Israel.

That was marked by a campaign of civil disobedience by Palestinians in the occupied territories, together with an increase in suicide attacks on Israel, often in response to Israeli attacks in the West Bank and Gaza.

Hamas had boycotted elections to the Palestinian Authority, as it was a product of the 1993 Oslo peace process, which the group opposed.

But as the second intifada wore on and the Palestinian Authority became weaker in the face of the Israeli military occupation, Hamas decided to participate in Palestinian parliamentary elections in 2006.

The group, promising to fight corruption and resist Israeli occuption, defeated their Fatah rivals convincingly, bringing Haniya to power as prime minister.

International isolation

However, the US, European Union and Israel had branded Hamas a terrorist organisation and, following its 2006 election victory imposed severe economic sanctions on the Palestinian territories.

Hamas took control of Gaza in 2007 after months of Palestinian infighting [AFP]

The Palestinian Authority, which relies on international aid to pay workers, was thrown into crisis by the sanctions and political tensions between Hamas and Fatah grew.

Rival members clashed in the West Bank and Gaza as the two sides fought a bloody battle for control in the territories.

The two parties agreed to form a unity government in early 2007 in an attempt to gain new international aid.

That bid failed and the struggle for power culminated in Hamas militarily taking over Palestinian institutions in the Gaza Strip in June 2007 and Mahmoud Abbas, the Palestinian president and Fatah leader, taking power in the West Bank.

Since then, the group has been increasingly isolated by Israel, which has targeted the territory with increasing military and economic sanctions, including cuts in electricity supplies.

After the end of yet another truce in December 2008, Israel launched a massive military assault on the Gaza Strip, in what it says is an attempt to halt continued rocket attacks emanating from Gaza.

The massive assault promises to be one the biggest tests Hamas has faced in its 21-year history.