About 1,000 people were arrested after two men detonated a bomb in central Ankara, close to the Interior Ministry and Parliament, which was set to reconvene for the first session of the legislative year only hours later. Police shot dead one of the assailants while the other died in the apparent suicide blast outside the ministry.
Turkish Foreign Minister Hakan Fidan said on Wednesday the two attackers came from Syria and had also been trained in that country.
"From now on, all infrastructure, large facilities and energy facilities belonging to [armed Kurdish groups] in Iraq and Syria are legitimate targets for our security forces," he said.
The PKK has been fighting in an insurgency in Turkey since 1984 and has bases in remote regions of Iraq and Syria.
Turkey regularly strikes PKK-affiliated sites in neighbouring Iraq and Syria, hitting 20 sites in Iraq on Sunday, according to the Interior Ministry.
It struck another 16 sites in northern Iraq on Tuesday, before renewed airstrikes on Wednesday.
The defence ministry said it hit 22 sites "to eliminate terrorist attacks against our security forces and ensure our border security."
Caves, shelters and warehouses were hit in the Wednesday strikes, which killed a "large number of terrorists," it added.
Hundreds of villages in northern Iraq have been emptied due to the decades-long Turkey-PKK conflict, with many civilians caught in the crossfire of Turkish attacks and PKK bases in their areas.
Iraq, which regularly condemns the strikes, will send Defence Minister Thabet Al Abbassi to Ankara on Thursday to meet his Turkish counterpart Yasar Guler, local media reported.
Ankara sees the YPG as a Syrian offshoot of the PKK, designated a terrorist group by Turkey and its western allies including the US and EU.
In 2019, Turkey launched an offensive against the YPG in north-eastern Syria, displacing hundreds of thousands of people in "Operation Peace Spring".
Also on Wednesday, Turkey's state-run Anadolu Agency reported the MIT intelligence service had killed a terrorist in Syria who plotted an attack on Istanbul's Istiklal Avenue last year.
Nabo Heyri was part of a cell plotting terror attacks in Turkey, it said.
The bombing killed six people.