The Kurdistan Freedom Falcons, the group which has claimed responsibility for bomb blasts earlier this week in Istanbul and two Turkish Mediterranean tourist resorts, is a small shadowy group, often described as an offshoot of Turkey's main Kurdish rebel group, the PKK.
The Falcons have claimed a string of attacks in Turkish resorts
But it is far from clear how closely the two groups might be linked.
The Falcons first came to international attention about two years ago at a time when there were increasing reports of splits within the PKK.
Since then the Falcons have claimed responsibility for a variety of attacks including an increasing number of bombings targeting civilians in tourist resorts.
The group swears allegiance to imprisoned PKK leader Abdullah Ocalan, and is widely regarded as an offshoot of the much larger PKK.
The PKK maintains the Freedom Falcons is a splinter group over which it has no control.
But many Turkish officials and analysts believe "Freedom Falcons" is simply an alias of the PKK, or that the group at least has PKK support.
Neither is it entirely clear what the Falcons' aims are, and there are questions about how far the two groups see eye-to-eye on strategy.
Last year the PKK leadership, which has claimed responsibility for many attacks against military and government targets in the largely Kurdish south-east of the country, condemned some of the attacks claimed by the Freedom Falcons in western tourist resorts.
The Falcons swear allegiance to PKK leader Abdullah Ocalan
The latest attacks claimed by the Falcons come only days after the PKK offered another conditional ceasefire in its long-running conflict with the Turkish government.
The PKK implemented a five-year unilateral ceasefire after Abdullah Ocalan was arrested in 1999, but resumed armed activities in 2004.
After Mr Ocalan's arrest it also dropped its demands for an independent Kurdish state within Turkey.
In recent years it has instead been calling for Ankara to open a political dialogue with the PKK, increase cultural rights for Turkey's Kurds and release imprisoned PKK members, including Abdullah Ocalan.
But Ankara, which regards the PKK as a terrorist organisation, has ignored all such calls.
Over recent months, the PKK has come under increasing pressure.
Ankara has mounted a major military offensive to combat PKK operations on its soil.
Turkish and Kurdish intellectuals have called on the group to lay down its arms.
And there have been reports that Iran, which has its own restive Kurdish population, has been sporadically shelling remote areas of northern Iraq, where fighters from the PKK and a sister organisation which conducts operations in Iran are based.