The Turkish foreign ministry confirmed in a statement that an "employee was martyred" in an "atrocious attack" outside the consulate in Arbil.

Turkish presidential spokesman Ibrahim Kalin vowed on Twitter that "the necessary response will be given to those who committed this treacherous attack".

Kalin added that efforts to find the gunmen responsible "had begun" but did not speculate over who might be responsible for the attack.

No group immediately claimed responsibility for the attack.

A police source in Iraq said three people including the Turkish vice consul were killed in the attack "targeting the consul and the consulate's employees in a restaurant".

Turkish officials did not provide information on the identity of the Turkish official killed.

The Kurdish region is on the border with Turkey.

In May, Turkey launched an operation in northern Iraq against the outlawed Kurdistan Workers' Party (PKK), which has waged an insurgency against the Turkish state since 1984.

The PKK, which operates bases in the Qandil mountain area of the autonomous Kurdish region, is proscribed as a terrorist organisation by Ankara and its Western allies.