The Kurdistan Freedom Falcons, or TAK is claiming responsibility for a deadly double bombing in Istanbul.
38 people -- mostly police officers -- were killed when a car bomb and a suicide bomber detonated outside a soccer stadium Saturday night.
The group posted on its website that the attack was retaliation for ongoing violence in the country's southeast and the imprisonment of leader of the Kurdistan Workers' Party.
Officials in Turkey said they detained three people for posts made on social media following the deadly twin bombing.
The prosecutor's office said it was investigating any posting or sharing on social media platforms "that attempted to praise terrorism or terrorist organizations.''
In a show of defiance, more than one-hundred demonstrators subsequently marched along Istanbul's coastline toward the soccer stadium.
Turkey's constitutional Court issued a statement condemning the bombing and added the attackers "will never reach their goals.''
The country declared a national day of mourning.