GAZIANTEP, Turkey — Turkish warplanes took to the skies overnight Monday and launched airstrikes—not against Islamic militants as Washington has urged, but targeting Kurdish separatists in southeast Turkey. The attacks risk inflaming Kurdish anger and shattering a two-year peace process between the government and insurgents of the Kurdistan Workers’ Party, the PKK. The strikes also will complicate President Barack Obama’s efforts to persuade Turkey to join in the fight against the so-called Islamic State, widely known as ISIS or ISIL.

For the first time since the launch in 2012 of a faltering peace process between Ankara and Turkey’s Kurds, Turkish warplanes carried out significant airstrikes on the outlawed PKK, striking targets in five different locations in the town of Daglica—near Turkey’s borders with Iran and Iraq.

Turkish media reported the airstrikes came after Kurdish separatists attacked a military barracks nearby.

Already Kurds have mounted days of furious street protests against the Turkish government in more than a dozen towns because of Ankara’s refusal to intervene militarily to defend the Syrian border town of Kobani from Islamic militants. The protestors—along with U.N. officials—have been calling on Ankara to permit Kurds from Turkey and elsewhere in Syria to relieve the flagging defenders, but to no avail. The Kurds accuse the Turkish government of seeing them as a greater danger than Islamic militants.

The plight of Kobani has added also to tensions between Washington and Ankara, which has declined to play any role so far in the U.S.-led coalition against ISIS. So far the Turkish government is refusing to allow a NATO base at Incirlik in southern Turkey to be used for airstrikes against the group. But the Turks have agreed that Turkish territory can be used for the training of 2000 relatively moderate Syrian rebels.

According to Turkey’s Hurriyet newspaper, the Turkish airstrikes caused “major damage” to the PKK, which has waged a 30-year-long insurgency for self rule, and is considered a terrorist organization by the United States. Turkish military officials said they had no choice but to respond in the “strongest terms” to PKK provocation, saying the strikes were in retaliation for three days of PKK attacks on a military outpost in Hakkari province near the Iraqi border.

PKK sources say they suffered no casualties—they insist there was also an artillery bombardment on their bases. The claims of either side have not been independently verified.

Prime Minister Ahmet Davutoglu told a news conference: “Yesterday there was very serious harassing fire around the Daglica military outpost. Naturally it is impossible for us to tolerate this. Hence the Turkish armed forces took the necessary measures.” He did not specify whether airstrikes were involved.

At the weekend one of the founders of the PKK, Cemil Bayik, warned that the separatist group had called veteran fighters back to Turkey from their sanctuary in Iraqi Kurdistan and could resume their insurgency. He said the peace process was imperiled after Kurdish protests sparked by the government’s policy on Syria left dozens dead and nearly four hundred injured.

“We have warned Turkey,” Bayik told German broadcaster ARD. “If the state carries on like this, then the guerrillas will resume the war of defense in order to protect the people.” When the peace process began the PKK moved many fighters to a base at Mount Kandil in northern Iraq.

The PKK’s overall leader, Abdullah Ocalan, also warned last week that the peace process could be over if Kobani falls. His words are echoed by PKK activists, who have been observing from villages along the border the month-long siege of the Syrian border town. After the news of the airstrikes, a PKK sympathizer in the small village of Mwasser just across the border from Kobani warned: “There will be a lot of war here, if the Islamic militants capture Kobani.”

The collapse of the peace process and a resumption of the Kurdish insurgency in Turkey would be a new source of turmoil in a region already engulfed by civil war in Syria, an insurgency by ISIS in Iraq and an international campaign against Islamic militants.

Ocalan has given the Turkish government until October 15 to draw a roadmap for the peace process, but PKK sources say there are no signs that President Recep Tayyip Erdoğan will meet the deadline. At the weekend Erdoğan insisted he would do everything to keep the peace process going, denouncing hardliners among the Kurds who, he said, were determined to sabotage the search for a deal.

And he pointed the finger at the Kurdish protestors for endangering the peace, saying in a televised speech: “Everyone must know that the acts of violence, vandalism and pillaging that we saw in the last days have nothing to do with Kobani.”

The Turkish airstrikes underscore the complexity of the regional politics—a diplomat here likened the scene to a can of worms with all the worms knotted: The U.S. is launching airstrikes on Kobani to help the Kurdish defense forces, or YPG, there to hold off Islamic militants and the YPG is an offshoot of the PKK, which is designated a terrorist organization by Washington and is now being attacked by Turkey, a NATO ally.

The PKK’s Ocalan is expected later Wednesday to issue a statement on the airstrikes and what steps the outlawed party will take. Ahead of his statement the PKK issued a condemnation of the strikes. “For the first time in nearly two years, an air operation was carried out against our forces by the occupying Turkish Republic army,” the PKK said. “These attacks against two guerrilla bases at Daglica violated the ceasefire.”

Kurds along the border say the strikes show whose side Erdoğan is on—they accuse him either of turning a blind to ISIS, which has used Turkey as a logistical base, or actively helping it to grow. They are not the only ones who argue the Turkish government has assisted Islamic extremists. Dengir Mir Mehmet Fırat, one of the founders of Erdoğan’s ruling Justice and Development Party, or AKP, says the president has backed Islamic militants, including ISIS. In a newspaper interview Sunday, he claimed the government had assisted the militants with arms and funds. He added: “All these miscalculated policies have brought Turkey to the point we are facing now.”