An image from an aircraft cockpit video released by Turkey's state-run agency, Anadolu, of Turkish warplanes reportedly striking Islamic State group targets in Syria. Credit:AP It is the first time Turkish jets have attacked IS positions in Syrian territory, while its attacks on the outlawed Kurdistan Workers Party (PKK) in the north of Iraq are its first in four years. In a letter to United Nations Secretary-General Ban Ki-moon and the UN Security Council seen by the Reuters news agency, Turkey justified its decision to conduct air strikes against IS militants in Syria by claiming the Syrian government was neither capable nor willing to tackle the radical Islamist group. The Institute of the Study of War described Turkey's air strikes in Syria as marking "a major shift in Turkish policy which will provide [an] immediate boost to US efforts to degrade and ultimately defeat IS". Meanwhile, the attacks on the Kurdish positions effectively marked the end of a two-year ceasefire and a tenuous peace process designed to end the conflict between Turkey and the PKK that has killed more than 40,000.

The security fence on the Turkish-Syrian border, near the south-eastern town of Akcakale in Turkey's Sanliurfa province. Credit:Reuters Turkish Prime Minister Ahmet Davutoğlu announced the next phase of the air strikes at a media conference on Saturday, vowing to continue the operations "as long as the threat remains". Turkish police detained 590 alleged terrorists, including 37 foreigners, in simultaneous operations launched in 22 provinces against IS, PKK, and DHKP-C (Revolutionary People's Liberation Front) on Friday and Saturday, he said. The anti-terror campaign follows the death of 32 people in the south-eastern Turkish town of Suruc – a majority Kurdish town – on Monday in a suicide attack linked to Islamic State. Four Turkish police officers were killed in a revenge attack claimed by the PKK.

Despite the Turkish Prime Minister insisting that his Iraqi Kurdish counterpart, President Masoud Barzani, had expressed his "solidarity" with the Turkish government over the air strikes, President Barzani released a statement on Saturday expressing "his distress that the situation had developed to such a dangerous level". "Many years of dialogue is better than one hour of war," he said in the statement. "Therefore, Kurdistan region will pursue any method to control the situation and [reverting] to the peace process is the best . . . solution." His nephew and Kurdistan's Prime Minister, Nechervan Barzani, "strongly rejected" the attacks, while the former head of Kurdistan's Socialist Democratic Party, Mahmoud Othman, condemned the air strikes on Twitter, urging the world to "not sit silently" over the attacks. Turkey's leaders are also concerned about the growing strength of Syria's Kurdish YPG militia, which is linked to the PKK, which has emerged as an effective force against Islamic State extremists. Backed by the US-led coalition air strikes against Islamic State, the YPG controls as much as half of Syria's 800-kilometre border with Turkey, and Ankara is determined to prevent the Kurds creating an independent state in the north of Syria.

In what many analysts viewed as a related move, Turkish Foreign Minister Mevlut Cavusoglu continued to push for a safe zone for Syrian refugees and a no-fly zone – a position the US has consistently rejected – in recent public comments. "When areas in northern Syria are cleared of the [IS] threat, the safe zones will be formed naturally," Mr Cavusoglu told a news conference. "We have always defended safe zones and no-fly zones in Syria. People who have been displaced can be placed in those safe zones." Turkish President Recep Tayyip Erdogan and his ruling AK Party have faced repeated allegations that they have been secretly backing Islamic State by facilitating the transfer of fighters and weapons between Syria and Turkey; a claim the government has strenuously denied. Turkey was partly driven by its fear that Kurdish factions were too closely aligned to Iran and that any change in Kurdish control of territory in Syria's north would foster further instability within Turkey, said Akin Unver, an assistant professor of international relations at Kadir Has University in Istanbul.

"If Syrian Kurds acquire the entire northern part of Syria, Turkey will be cut off from the Middle East by a Kurdish belt . . . its only opening is Aleppo, all other options are sealed off by Kurdish cantons," he told Fairfax Media. Complicating the issue was the fact that the government of President Erdogan was beholden to a conservative power base, who, even though they did not support Islamic State, disliked the idea of Turkey attacking other Sunni Muslims, he said. "Politically [it's] very costly for any party in Turkey to attack other Sunnis . . . while for the Kurds, the targets Turkey has been hitting in northern Iraq are exactly the same ones they targeted 20 years ago," he said. "This is not strategic, this is to save public face that Turkey is targeting IS." Follow FairfaxForeign on Twitter