Kurdish YPG fighters
Kurdish YPG fightersFlash 90

The Turkish defense ministry said early on Sunday it carried out air strikes against outlawed Kurdish militant bases in northern Syria and northern Iraq, which it said were used to carry out attacks on Turkey, Reuters reported.

The strikes targeted bases of the outlawed Kurdistan Workers Party (PKK) and the Syrian Kurdish YPG militia, which Turkey says is a wing of the PKK, the ministry added in a statement.

Turkey said on Tuesday it plans to pursue targets in northern Syria after it completes a cross-border operation against the PKK militants in Iraq, following a deadly bomb last weekend in Istanbul.

The government blamed Kurdish militants for the blast on Istanbul's Istiklal Avenue last Sunday that killed six people and injured more than 80.

No group has claimed responsibility for the attack, but the PKK and SDF have denied involvement.

YPG is a Kurdish group with ties to Kurds in Turkey, including the PKK. The US makes a distinction between the YPG and the PKK, but Turkey does not and considers both to be terrorist organizations.