Turkey launched deadly airstrikes over northern regions of Syria and Iraq targeting Kurdish groups that Ankara holds responsible for last week's bomb attack in Istanbul.
The Turkish Defense Ministry, in a statement, said it was targeting areas “used as a base by terrorists”.
The ministry cited Turkey's right to self-defence under Article 51 of the United Nations Charter while launching an operation which it called Claw-Sword.
The airstrikes came after a bomb rocked a bustling avenue in the heart of Istanbul on November 13, killing six people and wounding over 80 others.
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Turkey has invaded northern Syria three times since 2016 and already controls some territories in the north. Earlier this year, Erdogan threatened another military operation in the border area.