Turkish warplanes resumed air strikes against Kurdistan Workers Party (PKK) and Islamic State group positions in Iraq early on Saturday.

“The operations will continue for as long as threats against Turkey continue,” Turkish Prime Minister Ahmet Davutoglu told reporters before leaving Ankara for Istanbul where he is scheduled to meet with Turkish President Recep Tayyip Erdogan.

“Those who threaten [Turkey] will face the response,” he added.

A PKK spokesman in Iraq, Bakhtiar Dogan, told AFP one fighter was killed and three wounded in the strikes.

A medical source north of the Iraqi Kurdish city of Dohuk said two civilians, including a 12-year-old boy, were also wounded, although this could not be independetly confirmed.

Following the second day of bombing, the PKK said that its truce with Ankara had lost its meaning.

"The truce has no meaning anymore after these intense air strikes by the occupant Turkish army," the PKK said in a statement on its website.

The PKK then went on to denounce the "aggression of war" by Turkey and vowed "resistance".

On Saturday afternoon unidentified assailants attacked the riot police unit on duty near the Cemal Kamaci sport complex, injuring three policemen and a civilian, police said.

It is unclear if the attack was carried out by the PKK, with the police launching an investigation to find the perpetrators.

Kurdish regional President Massud Barzani, seen as close to Turkey, has denounced the escalation, telling Davutoglu that he was displeased with the "dangerous level the situation has reached".

Barzani's office said in a statement that he "requested that the issue not be escalated to that level because peace is the only way to solve problems and years of negotiations are better than one hour of war."

"Mr Barzani is ready to do anything within his means to appease this tension and go back to a situation of peace," the statement added.

Turkey first bombed military positions of Turkey's rebel PKK in neighbouring Iraq on Friday.

"At around 11:00 pm [20.00 GMT] tonight, Turkish warplanes started bombing our positions near the border, accompanied by heavy artillery shelling," PKK's Dogan, told AFP.

In addition to the air raids, Turkish ground forces carried out artillery strikes against IS in Syria and the PKK in northern Iraq, Davutoglu's office said in subsequent statement.

Tensions with PKK

The PKK, which is banned in Turkey and has long had a presence in Iraq, has several training camps in Dohuk, a province that also borders Kurdish areas of Syria.

The strikes appear to be in response to PKK attacks on Turkish security forces in the past few days in which three police were killed. The PKK said that it carried out the attacks in retaliation for Ankara's inaction over IS, blaming the Turkish authorities for not doing more to prevent a suicide attack in Suruc, southern Turkey, last week. More than 30 pro-Kurdish activists were killed and more than a 100 people injured in the attack, widely blamed on IS.

Turkish authorities have repeatedly denied the allegations. On Saturday, President Recep Tayyip Erdogan's office issued fresh denials.

"The recent groundless, immoral allegations that Erdogan, his son Bilal Erdogan and his daughter Sumeyye Erdogan have ties with Daesh [IS], are a part of a smear campaign, conducted against Turkey, and are out-and-out lies,” the statement said.

“These ugly slanders, fabricated by certain foreign websites that support the Assad regime and its collaborators, have been quoted by some circles, known for their anti-Turkey attitude, and reported under the guise of news by certain websites that virtually made a profession out of lying."

The Turkish security services have also taken aim at the PKK, on Saturday releasing damning reports that suggest the group has carried out 2,000 acts of violence across Turkey in 2015.

These alleged acts include armed attacks on police and civilians, assaults with stones and sticks, bomb attacks, as well as hijacking or abduction, according to police statistics, security sources told Anadolu.

The group has set at least 31 vehicles on fire during the last week, one source said.

The PKK is considered a terrorist organisation by Turkey and the US, and has been engaged in a guerrilla war with the Turkish state since 1984. The conflict has claimed 40,000 lives and led to the destruction of thousands of Kurdish villages.

While a peace process had been started in recent years and a truce agreed in 2013, with former prime minister and now President Erdogan coming closer to a deal than any previous leader, tensions over the rise of the IS group appear to have derailed progress.

Turkish police on Friday and Saturday swooped on suspected members of the IS group and the PKK.

A total of 590 people including at least 37 foreigners were detained, Davutoglu said, adding that the raids took place across Turkey. This includes three men suspected of carrying out a deadly attack against Turkish police on Friday.

Police sources said that two suspects were detained in Semdinli’s Moda neighbourhood and one in Altinsu village.

As well as IS and the PKK, the operation targeted suspected members of the PKK's youth wing, the Patriotic Revolutionary Youth Movement (YDG-H), and the Marxist Revolutionary People's Liberation Party Front (DHKP-C).

"Turkey will show the strongest reaction to the slightest movement that threatens it," Davutoglu said.

Turkey also have launched a crackdown on pro-Kurdish media with bases outside of Turkey on Saturday. Website for pro-Kurdish Rudaw, BasNews, DİHA, ANHA and Ozgur Gundem newspaper all appear to have been blocked, daily Hurriyet reported. Twitter and Facebook were also reportedly operating more slowly due to government monitoring.

“The Rudaw website is blocked and people have no access to the digital portal, as a result users of Rudaw’s various news applications could not benefit from website’s news services since this morning,” a Rudaw reporter in Turkey said.

Anti-IS raids

The last 24 hours have also seen an apparent escalation against IS targets, with Turkey hitting their positions in Iraq and Syria and private broadcaster NTV reporting that Turkish artillery had continued to shell IS in northern Syria on Saturday.

Turkey was initially seen as a relatively unwilling partner in the US-led anti-IS campaign which began last year, but Ankara this week allowed the anti-IS coalition the full use of its airbases, marking a turning point in its policy post-Suruc, the first major attack IS has staged on Turkish soil.

Turkey has long been pushing its Western allies to set up some sort of safe area or buffer zone in northern Syria. The West has shown itself unwilling to go that far despite the rise of IS and other militant groups and the continued violence and gross human rights violations and possible war crimes committed by the government of Syrian President Bashar al-Assad.

Turkish Foreign Minister Mevlut Cavusoglu, however, on Saturday stressed that eradicating IS would "automatically lead" to the formation of a safe zone.

"We attach great importance to our cooperation with the U.S. and believe that it will result in an effective fight against the Daesh threat," he said.

"We have kept saying that refugees in Turkey and neighboring countries as well as those displaced within Syria and Iraq could be placed in such safe zones."

Reports have appeared in the Turkish press insisting that the US and Turkey have now agreed to set up 98 kilometre long and 40 kilometre wide IS-free zone near parts of northern Syria at present under IS control.

Once cleared of IS, the opposition Free Syrian Army would be moved in to control the area, the reports said

Turkey is at present home to at least 1.8 million Syrian refugees, with around 265,000 of them living in refugee camps along the border.