Turkish police arrested three suspects on Tuesday for allegedly sending a shipment of four unmanned aerial vehicles (UAVs) to terrorist groups in Syria, security sources said.
The suspects were arrested in Istanbul and the southern Adana province, while another of Syrian nationality was held in the southern Hatay province, said the sources who asked not to be named, due to restrictions on speaking to the media.
Acting on a tip-off received earlier this month, Adana police detained another suspect in a cargo office, while allegedly trying to send drones to people with links to terrorist groups in Syria.
Prosecutors in Adana issued arrest warrants for three other people over alleged links to terrorist groups.
Although the statement did not mention any specific terrorist group, Turkish forces have long been conducting operations against the terrorist group YPG/PKK in the region.
In its more than 30-year terror campaign against Turkey, the PKK -- listed as a terrorist organization by Turkey, the U.S. and EU -- has been responsible for the deaths of 40,000 people, including women, children and infants. The YPG is the PKK's Syrian offshoot.