Istanbul, Turkey (CNN) – A car bomb exploded Sunday in southern Turkey, killing two security officers and wounding four other people, officials said.
The attack was launched when a vehicle carrying security personnel was ambushed on its way to an emergency call, the Diyarbakir provincial office said.
Diyarbakir is a province in southeastern Turkey, a heavily Kurdish area, and is home to the city of the same name.
No one has been arrested in connection with the explosion, officials said
The bombing comes as Turkey grapples with a wave of violence near its southern border with Syria and is ramping up its effort to fight terrorists.
On Thursday, at least five ISIS militants in northern Syria approached the border and fired on a Turkish border unit, killing a soldier and wounding two others, the Turkish military said.
Authorities say ISIS was also to blame for a suicide blast Monday that killed more than 30 people in Suruc, a Turkish town that borders Syria.
And after the Kurdistan Worker’s Party, or PKK, killed two Turkish police officers Wednesday, Prime Minister Ahmet Davutoglu vowed to take action.
“We will not stay silent in the face of those who kill our police officers in their sleep,” Davutoglu said.
Turkey initially decided to attack ISIS during a national security meeting Thursday headed by Davutoglu. Turkish forces arrested 590 suspected terrorists, bombed ISIS positions in northern Syria and targeted the PKK in strikes in a daylong operation Saturday.
It was the first time Turkey had attacked ISIS and the PKK simultaneously.
“This is a big deal for the U.S. and the coalition, to get the Turks on their side,” retired Air Force Lt. Col. Rich Francona, a military analyst, told CNN. “This is a game-changer.”
The U.S. reached a tentative agreement with Turkey last week to increase U.S. and coalition access to Turkish air bases.
“We attach great importance to our cooperation with the U.S. and believe that it will result in an effective fight against the ISIS threat,” Turkish Foreign Minister Mevlut Cavusoglu said.
An act of ‘retribution’
The PKK issued a statement declaring a 2013 ceasefire agreement with Turkey to be over, according to the pro-PKK Firat News Agency. The statement referred to the slaying of the two police officers, calling it an act of “retribution” carried out by “local branches” without orders from the central PKK command.
Kurdistan Regional President Masoud Barzani expressed concern about Turkey’s bombardment of PKK positions in Iraq’s Kurdish area, but he called on all parties to stay calm “because peace is the only solution to problems, and years of dialogue is better than an hour of fighting.”
Turkey believes the PKK is exploiting ISIS’ efforts. The PKK has been fighting for independence since 1984 and is feared to be making gains.
The group is considered a terrorist organization by the United States, but PKK militants have come to the aid of Kurdish Peshmerga fighters who have been fighting ISIS in northern Iraq.