Mushir al-Masri, a spokesman for Hamas, said at the time that the attacks were in response to the killing of more than 150 Palestinians by Israeli soldiers in the latter half of 2005.
He said that Israeli forces had also wounded 1,000 Palestinians and detained another 3,500.
In 2006, Khalid al-Batsh, an Islamic Jihad leader, refused to join Hamas in a power-sharing bid after its election win in the Palestinian parliament.
"Islamic Jihad will not join the coming cabinet," he said.
"If the government will have an agenda of resistance, we will support it."
Batsh said any long-term ceasefire with Israel would be useless and Islamic Jihad "rejects it completely".
Also that year, Israel arrested and assassinated senior Islamic Jihad members and those it accused of orchestrating rocket attacks and suicide bombings in Israel.
The Israeli military went so far as using fighter planes to kill a senior Islamic Jihad member in Sidon, in southern Lebanon.
Islamic Jihad responded with suicide operations and firing homemade rockets at Israeli settlements and cities.
The Islamic Jihad movement was founded in the late 1970s by Fathi Shaqaqi, who served as its secretary-general, with a group of Palestinian youths who were studying at Egyptian universities.
Al-Shaqaqi was assassinated by Israeli agents in Malta in 1995.
Ramadan Shalah, who lives in exile in Syria, assumed the leadership of the movement after al-Shaqaqi's murder.
The group has adopted several principles that govern its political and military approach to Israel and its occupation of Palestinian lands.
The groups maintains that Palestine, with its borders marked from the Jordan river to the Mediterranean sea, is Islamic Arab land and it is religiously prohibited to compromise or surrender any of it.
Israel's existence in Palestinian territory is seen as illegitimate.
Israel is also viewed as a spearhead of Western colonisation against the Islamic nation, existing to dominate and divide and impose backwardness by the Western powers on the Islamic nation.
Islamic Jihad works to mobilise Palestinians and prepare them for political and military jihad through educational and organisational means.
The Al-Quds Brigades, its military wing, became active during the 1987 intifada (uprising) by launching operations against Israeli military and non-military targets, both inside the occupied territories in 1967 or within the Green Line.
The movement clashed with the Palestinian Authority (PA) many times because of its rejection of the Oslo peace agreements.
Islamic Jihad says suicide attacks inside Israel and against Israeli civilians are legitimate, a stance that is rejected by the PA.
After the September 11, 2001, attacks, the US added Islamic Jihad to the list of "terrorist" organisations.
January 20, 2006: A bomber blows himself up in a crowded pedestrian shopping centre near Tel Aviv's central bus station, injuring at least 22 people, police say.
February 5, 2006: Adnan Bustan, 28, the Islamic Jihad's senior bomb-maker is among two killed in the Zeitun neighbourhood of Gaza City.
Islamic Jihad confirms he headed the armed group's "engineering and manufacturing unit" that produces rockets and explosives.
February 14, 2006: Al-Quds Brigades fires two rockets into the industrial zone of the Mediterranean port city of Ashkelon in southern Israel, causing no casualties or damage.
Israel responds by continuing its shelling of the northern Palestinian town of Beit Hanoun damaging two apartment blocks. No casualties reported.
February 21, 2006: The head of the Al-Quds Brigades in the West Bank region of Nablus is killed by the Israeli army.
March 1, 2006: Khalid al-Dahduh, the leader of the Al-Quds Brigades in the Gaza Strip, is killed when the vehicle in which he is travelling explodes after an Israeli air raid.
March 27, 2006: Islamic Jihad responds by killing two Israelis in an explosion near the border with the Gaza Strip. Islamic Jihad says the attack is designed to disrupt Israel's general elections.
April 17, 2006: Islamic Jihad responds to what it calls "Israel's deadly raids in Gaza" with a suicide bombing in a crowded restaurant in Tel Aviv, killing nine.
May 26, 2006: Israeli aircraft kill Mahmud al-Majzub, an Islamic Jihad leader, and his brother in the southern Lebanese city of Sidon.
July 28, 2006: Two Islamic Jihad fighters are killed in an Israeli raid in the West Bank.
January 29, 2007: Three Jewish civilians killed in Eilat bakery bombing, claimed by Islamic Jihad jointly with al-Aqsa Martyrs Brigades