The joint intelligence-sharing program targets the Kurdistan Workers Party (PKK), a militant organization that campaigns for a separate homeland for Turkey’s Kurdish minority. Washington and Ankara have both designated the group a terrorist organization, and have been working jointly to combat it since at least 1997. According to Reuters, the United States military has been carrying out surveillance on the PKK using unmanned surveillance drones that fly out of Turkey’s Incirlik air base. Much of the surveillance focuses on the regions of Turkey that border with Iraq and Syria, where the PKK has a strong grassroots presence.

But Washington decided to suspend the program indefinitely last October, said Reuters. The decision was allegedly taken after Turkish troops invaded Syria in order to push back Kurdish rebels and establish a Kurdish-free buffer zone along the Turkish-Syrian border. The news agency cited four American officials, who did not wish to identify themselves, “due to the sensitivity of the matter”. It also cited an unnamed Turkish official, who confirmed that the intelligence-collection program had been terminated.

The American officials told Reuters that the suspension of the program would place strains on the ability of the Turkish military to respond to the challenges of its ongoing guerrilla war against Kurdish militants in northern Syria, as well as within Turkey. It will also make “the anti-PKK campaign more […] costly for Turkey”, one of the officials told the news agency.

Reuters said it contacted the United States Department of Defense, but was told by a spokeswoman that the Pentagon would “not provide details on operational matters”. A spokesperson from the United States Department of State told Reuters that its representatives could “not comment on intelligence matters”. The Turkish Ministry of Defense did not return requests for comment.