The group has grown from small beginnings in Gaza's refugee camps
The Popular Resistance Committees group's origins lie in local militias that were set up in the early days of the second Palestinian uprising, or intifada.
It is regarded by observers as a fringe group, consisting mainly of dissident or breakaway members of the mainstream Fatah movement and former Palestinian security officials.
However, members of other militant Palestinian factions, such as Hamas and Islamic Jihad, are also represented.
It emerged at the end of 2000, with the aim of defending Palestinian refugee camps during Israeli incursions.
However, the PRC increasing moved towards launching its own attacks, especially against Israeli military and civilian targets in the Gaza Strip.
It has also been involved in internal Palestinian struggles, culminating in the killing of presidential security adviser Moussa Arafat, which the PRC claimed on 7 September 2005.
The group was founded by a former Fatah member from Rafah in southern Gaza, Jamal Abu Samhadana, and earned a reputation for armed resistance by blowing up three Israeli tanks using powerful remote-controlled bombs hidden at the roadside.
It was also blamed for the bombing of a US diplomatic convoy in October 2003, which it initially claimed, but then said was "against Palestinian interests".
Four PRC members were put on trial in a military court in Gaza for the attack, but they were released for lack of evidence.
The group has also fired mortars at Israeli settlements in Gaza.
PRC gunmen acting out an assault for the crowds in Gaza
It claimed responsibility, jointly with the Islamic Jihad organisation, for the killing of an unarmed Israeli settler and her four daughters in May 2004.
Two gunmen ambushed Tali Hatuel's car as she was driving from her Gaza settlement to Israel for a Likud party vote on proposals to pull out of Gaza.
Israeli military officials have alleged that the group is directly linked to the Palestinian police, describing it as the "terror wing" of the security services in the Palestinian territories.
The Israelis say that the Palestinian security service provides "vast financial and logistical support" for the committees, including military training, weapons and intelligence information.
But the group is also known to have made enemies with Moussa Arafat, a former military intelligence chief and cousin of late leader Yasser Arafat.
In September 2004 it claimed Gen Arafat's forces had tried to assassinate one of its leaders - and vowed revenge.
The following month he survived a car bombing, blamed on the group, which targeted a convoy in which he was riding. No-one was seriously injured.
It justified the subsequent killing of Gen Arafat because he "killed people, ordered assaults on fighters and had a big file of corruption".
The attack, involving about 100 fighters and in which Gen Arafat's son Manhal was also abducted, was seen as the most serious escalation to date in the power struggles between Palestinian factions following the death of Yasser Arafat late in 2004.
Bizarrely, just days earlier, the group had performed a military exercise at a "graduation ceremony" in Gaza that seemed to foreshadow the attack on Gen Arafat's house.
Hooded men in military fatigues armed with machine guns and rocket propelled grenades stormed buildings - daubed with crude Israeli symbols - and dragged pretend victims to the ground at gunpoint.
It seems unlikely that they will be allowed to act so publicly in the future.