ANKARA, Turkey (AP) — Attackers detonated explosives and opened fire on Turkey’s state-owned aerospace and defense company TUSAS on Wednesday, killing four people and wounding more than a dozen, President Recep Tayyip Erdogan said.

The two attackers – a man and a woman – were also killed, Interior Minister Ali Yerlikaya said.

Yerlikaya did not say which organization was behind the attack while the process of identifying the attackers was still ongoing. But Defense Minister Yasar Güler pointed the finger at the militant Kurdistan Workers’ Party (PKK).

“We give these PKK thugs the punishment they deserve every time. But they never come to their senses,” Guler said. “We will pursue them until the last terrorist is eliminated.”

The Islamic State and left-wing extremists have also carried out attacks in Turkey in the past.

“We have four martyrs. We have 14 wounded. I condemn this heinous terrorist attack,” Erdogan said during a meeting with Russian President Vladimir Putin on the sidelines of a BRICS meeting in Russia.

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Putin expressed his condolences. A statement from the US Embassy said Washington “strongly condemns today’s terrorist attack.”

TUSAS designs, manufactures and assembles civil and military aircraft, unmanned aerial vehicles and other defense industrial and space systems. Its UAVs have been instrumental in helping Turkey gain the upper hand in the fight against Kurdish militants both on its own territory and across the border in Iraq.

The attack came a day after the leader of Turkey’s far-right Nationalist Party, which is allied with Erdogan, raised the possibility that the jailed PKK leader could be granted parole if he renounces violence and disbands his organization.

Abdullah Öcalan’s group is fighting for autonomy in southeastern Turkey in a conflict that has killed tens of thousands of people since the 1980s. It is viewed as a terrorist group by Turkey and its Western allies.

The country’s pro-Kurdish political party, which also condemned the attack, noted that it came at a time when the possibility of dialogue to end the conflict had arisen.

Turkish media said the attackers arrived at the entrance to the TUSAS complex in a taxi on Wednesday. The attackers, who were carrying assault weapons, detonated an explosive device next to the taxi, causing panic and allowing them entry.

The Interior Ministry said the attack was carried out by two attackers and that the situation had been brought under control.

According to the HaberTurk television channel, the taxi driver was also among the dead.

Surveillance camera images broadcast on television showed a man in civilian clothes carrying a backpack and holding an assault rifle.

The interior minister said security teams were dispatched immediately after the attack began at around 3:30 p.m

After security forces entered the area, several shots were heard, the DHA news agency and other media reported. Helicopters flew over the area.

Vice President Cevdet Yilmaz said the aim of the attack was “Türkiye’s success in the defense industry.”

Associated Press writer Robert Badendieck in Hamburg, Germany, contributed.