At least eight Daesh terrorists were killed in northern Syria Friday during a military operation carried out by the Turkish Armed Forces and the U.S.-led coalition, Turkish security sources said Saturday.

The sources, who spoke with Anadolu Agency on condition of anonymity due to restrictions on talking to the media, said 31 Daesh targets had been hit in two airstrikes, while five buildings used by the terrorist group were also destroyed in the operation.

Daesh was reportedly preparing to attack Turkey from northern Syria, the sources added.

Since mid-January, Daesh rockets have been targeting towns and cities in southern Turkey, close to the Syrian border. A total of 21 people, including Syrians who had taken shelter in Turkey, were killed and more than 70 others wounded in such attacks.

Meanwhile, Turkish warplanes also carried out airstrikes on PKK targets in Iraq's Hakurk region and Turkey's southeastern provinces Friday.

According to Turkish General Staff's statement issued Saturday, Turkish fighter jets bombed Hakurk region between 1900GMT and 1946GMT, and destroyed two targets.

Eleven PKK targets were also destroyed in Turkey's Kars, Şırnak and Hakkari provinces, the statement added.

The PKK -- listed as a terrorist organization by Turkey, the U.S. and the EU -- resumed its 30-year armed campaign against the Turkish state in July 2015.