From suicide bombs to ceasefire hopes

· Hamas was formed in 1987 as the PLO moved away from its position that Palestine could only be liberated by an "armed struggle"

· The organisation is led by Sheikh Ahmed Yassin, a paraplegic cleric, who makes decisions in conjunction with a leadership council that also includes Abdel-Aziz al-Rantissi and Ismail Abu Shenab

· Hamas stands for the destruction of Israel and the formation of an Islamic Palestine in the territory of Israel, the West Bank and Gaza

· Its initial attacks on Israeli targets were relatively ineffectual until a militant settler, Baruch Goldstein, killed 29 Palestinians in the tomb of the patriarchs in Hebron in 1994. Hamas then initiated its strategy of sending suicide bombers to blow up Israeli civilian targets, particularly buses

· In 1996, after Israel had withdrawn from the Palestinian cities in the West Bank, the Israeli government ordered the assasination of Yihya Ayyash, a Hamas explosives expert, using a bomb in a mobile phone

· Over the following month Hamas killed more than 50 Israelis. The violence was stopped only when the Palestinian Authority clamped down on the group

· Hamas resumed its attacks on Israel when the intifada began in 2000. Its leaders are currently discussing whether to call an end to the violence