Origins and aims of groups targeting Israel

Hamas

Established in Gaza in late 1980s, as offshoot of religious groups associated with Egyptian Muslim Brotherhood. Name is acronym for Islamic Resistance Movement, but also means "zeal" in Arabic. Came to prominence during first intifada which began in 1987, presenting itself as rival to "secular" PLO. Seeks to replace Israel with Islamic Palestinian state. Founder and spiritual leader is Sheikh Ahmad Yasin, 63, who was paralysed by accident in his youth. Enjoys significant popular support among Palestinians. Sub-group known as Izzadin al-Qassem Brigades has carried out numerous attacks against Israel, including suicide bombings.

Palestine Islamic Jihad

Smaller of two main Islamic militant organisations, it developed in Gaza during 1970s and remains series of factions rather than cohesive group. Believes in destruction of Israel and creation of Islamic Palestinian state. Jihad factions also exist in Jordan, Lebanon and Syria. Fathi Shaqaqi, its leader, was assassinated by Israeli hit squad in Malta in 1995. Stepped up military activity last year, claiming numerous attacks against Israeli interests.

Al-Aqsa Martyrs' Brigades

Secular rival of Hamas and Jihad, formed in 2000 by activists linked to Yasser Arafat's Fatah organisation. Initially most attacks directed at Israeli soldiers and settlers in West Bank and Gaza but this year began suicide bombings inside Israel's 1967 borders, including first by female bomber. Has strong support in some refugee camps. Several leaders have been assassinated by Israel. Arafat does not recognise the brigades but Israel claims Palestinian Authority has given them financial support.

Popular Front for the Liberation of Palestine

Marxist-Leninist group founded in 1967 by George Habash, with uncompromising stance towards Israel. Active internationally in 1970s, and activity increased again last year. In August Israel killed its leader, Ali Abu Mustapha, with rocket fired into his office. In retaliation it killed Israel's extremist tourism minister, Rehavam Ze'evi.