Following a recent surge in violence in Turkey’s Kurdish-dominated southern regions, authorities detained over 250 people in 13 cities across the country on Friday. The arrests, made during early morning raids, targeted militants of the Islamic State group and members of the outlawed Kurdistan Workers’ Party (PKK), according to local media reports.

“Like it has been the case in the past, today, the state of the Republic of Turkey is determined in its multidimensional fight against the ISIL [ISIS] terrorist organization, the PKK terrorist organization and other international terrorist organizations,” Turkish prime minister’s office reportedly said in a statement released Friday. “All kinds of measures are being taken for our nation’s serenity and security.”

One person, allegedly a member of the outlawed Revolutionary People’s Liberation Party-Front (DHKP-C), was killed in shootout with police during the early morning “anti-terror operation” in Istanbul’s Bagcilar district, the state-run Anadolu Agency reported.

More than 5,000 security personnel were involved in the raid in Istanbul, where over 100 properties were searched, BBC reported. Additionally, arrests were also made in the cities of Ankara and Izmir, and in Sanliurfa province, located along Turkey’s border with Syria.

The raids come just days after 32 people were killed in a suicide bomb attack -- allegedly carried out by an ISIS sympathizer -- in the southern town of Suruc. On Wednesday, two days after the suicide attack, militants belonging to the armed wing of the PKK killed two Turkish police officers in the border town of Ceylanpinar as “revenge,” accusing them of collaborating with ISIS.

Following the incidents, Turkish planes -- for the first time ever -- began carrying out airstrikes on ISIS targets in Syria on Friday. Turkish forces also exchanged fire with ISIS fighters near the Syrian border, according to local media reports.

“They [ISIS] had been stockpiling and we suspect they were planning an attack at the Turkish border. We don’t know what they were aiming to achieve, but it could have been an attack for propaganda purposes,” a Turkish government official, speaking on condition of anonymity, told the Wall Street Journal, adding that the country has now entered a phase of “pre-emptive defense.”