The Turkish extreme left-wing group targeted in police raids across Europe wants to replace the Turkish government with a Marxist one.
DHKP-C inmates led a hunger strike over prison conditions
The Revolutionary People's Liberation Party-Front, DHKP-C, has carried out many attacks in Turkey, targeting the military and political establishment.
It is also hostile to what it calls US imperialism and Washington's close allies Britain and Israel.
The DHKP-C is branded as a terror organisation by the US and the EU.
Its attacks have claimed the lives of dozens of people since 1976, including two retired generals, a former justice minister and a prominent businessman, the AFP news agency reports.
The group also spearheaded a long-running hunger strike in Turkish prisons over the introduction of new high security jails.
More than 60 people died in the protest - most of them DHKP-C members - and another 30 inmates were killed when the army stormed prisons in December 2000 to end the campaign.
The bloodiest attack claimed by the group was on 10 September, 2001, when a suicide bomber killed himself and three other people in central Istanbul.
Ankara says about 100 policemen and soldiers along with 80 civilians have been killed in DHKP-C attacks.
The group has also targeted US military personnel and diplomatic missions.
A Turkish counter-terrorism expert told the BBC said the group had been trying to regain prominence by imitating the style of Osama Bin Laden's followers.
Senior DHKP-C figures fled abroad following Turkish police raids, and the group's leader Dursun Karatas has been on the run since escaping from an Istanbul prison in 1989.
Most of its activists are believed to live in exile in the four west European countries - Italy, Germany, Belgium and the Netherlands - which targeted it on Thursday.
Until 1994, the DHKP-C was known as Dev-Sol (Revolutionary Left), a Marxist-Leninist organisation which had earlier been called Dev-Yol (Revolutionary Path).
It recruited supporters mainly in high schools
The DHKP-C has been mainly active in Turkey's biggest city Istanbul.