ISTANBUL — Turkey's military and intelligence agency has "neutralized" the instigator of an attack that killed a Turkish diplomat in Arbil, northern Iraq, state-owned Anadolu news agency said on Friday.

The diplomat and at least one other person were shot dead on July 17 when a gunman opened fire in a restaurant in the capital of Iraq's semi-autonomous Kurdish region.

Anadolu said the instigator of the attack, identified as Erdogan Unal, a Kurdistan Workers Party (PKK) official, was "neutralized" on Wednesday. Turkish authorities commonly use that term to denote deaths but it can also refer to those wounded or captured.

The operation was conducted in Iraq's Qandil region, north of Arbil, where PKK fighters are based, Anadolu said, without giving further details.

The PKK, which is considered a terrorist organization by Turkey, the United States and the European Union, has led an insurgency against the Turkish state since the 1980s.

A security source said on Thursday that Turkey had carried out two separate air strikes in northern Iraq, killing the planners of the attack.

Security services in Iraq's Kurdish region said on Saturday they had arrested the brother of a Turkish lawmaker from the pro-Kurdish People's Democratic Party (HDP) on suspicion of planning the killing. The HDP has condemned the attack.

The shooting of the diplomat took place weeks after Turkey launched a new military offensive against Kurdish separatist militants based in northern Iraq.

Turkey and the ruling Kurdish party in Arbil, the KDP, have blamed the PKK for other incidents in northern Iraq including the storming of a Turkish military camp earlier this year. — Reuters