Turkish fighter jets and ground forces hit Islamic State militants in Syria and Kurdistan Workers Party (PKK) camps in Iraq overnight on Saturday, in a campaign Ankara said would help create a "safe zone" across swathes of northern Syria.
Turkey has dramatically cranked up its role in the U.S.-led coalition against Islamic State group since a suspected ISIS suicide bomber killed 32 people earlier this week in a town close to the Syrian border, while pledging to also target Kurdish militants.
This has raised concern about the future of the shaky Kurdish peace process. Critics including opposition politicians accuse President Tayyip Erdogan of trying to use the campaign against Islamic State as an excuse to crack down on Kurds.
The heightened security operations will go on for as long as Turkey feels threatened, Prime Minister Ahmet Davutoglu told a news conference. Islamic State has seized much of northern and eastern Syria four years into the country's civil war.
"These operations are not 'one-point operations' and will continue as long as there is a threat against Turkey," he said.
Turkey was long a reluctant member of the coalition against Islamic State, a stance that annoyed NATO ally Washington with the air strikes doing little so far to "degrade and destroy" IS capabilities, as President Barack Obama described their goal.
Ankara has now, for the first time, taken a front-line role in the battle, apparently spurred to action by the suicide bombing in the border town of Suruc.
Many of those killed in the attack were Kurds and it kicked off waves of violence in the largely Kurdish southeast by militants who say Erdogan and his Islamist-rooted AK Party have covertly supported Islamic State against Syrian Kurds.
Ankara denies the accusation.
Turkey staged its first-ever air strike on IS in Syria early on Friday, while police rounded up hundreds of suspected Islamist and Kurdish militants in cities and towns across the country. As of Saturday, nearly 600 people had been detained.
"It is unacceptable that Erdogan and the AKP government have made a fight against the Kurdish people part of their struggle against Islamic State," the pro-Kurdish Peoples' Democratic Party (HDP) said in a statement. "The military attacks, bombings, political detention operations and pressure must stop right away."
Once swathes of northern Syria are cleared of Islamic State militants, "safe zones will be formed naturally", Foreign Minister Mevlut 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," he said.
Turkey has long sought a "no-fly zone" or "safe zone" in northern Syria but met resistance from Washington, which says direct military pressure on Islamic State, not a "safe zone", is the best way to end the region's fighting and refugee crisis.
Ankara struck a deal with Washington this week allowing coalition forces to use Turkish bases for bombing raids against Islamic State, greatly shortening distances to targets and potentially making the aerial campaign more effective.
It was not immediately known whether the agreement would entail the creation of a safe or buffer zone.
The overnight air strikes hit Islamic State positions in Syria and PKK locations in northern Iraq, including warehouses and living quarters, Davutoglu's office said in a statement.
Simultaneously, Turkish land forces fired on Islamic State and the PKK, it said.
The attacks on the outlawed PKK, which has waged a three-decade insurgency against Turkey, could kill off stumbling peace talks between the group and Ankara, which were started in 2012 but have been stalled lately.
"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.
Erdogan took a big political risk in starting peace talks in 2012 with the Kurds, who represent nearly 20 percent of Turkey's population. They now accuse him of backtracking on promises.
Separately, Istanbul authorities said they would not let organizers go ahead with a peace march planned for Sunday, citing concerns about security and "dense traffic". The march had been organized with support of some opposition politicians.
(Addditional reporting by Gulsen Solaker and Orhan Coskun; Writing by David Dolan; Editing by Mark Heinrich)