Turkey plans to strike targets in northern Syria after it completes a cross-border operation against Kurdistan Workers' Party (PKK) insurgents in Iraq, a senior official said after a bomb blast in Istanbul over the weekend, Reuters reported.

The government blamed Kurdish militants for an explosion on Istanbul's Istiklal Avenue on Sunday that killed six people and wounded more than 80.

Threats from Kurdish fighters or Islamic State against Turkey are unacceptable, a Turkish official told Reuters, adding that Ankara would eliminate threats along its southern border 'one way or another.'

"Syria is a national security problem for Turkey. There is work being done on this already," the official said, declining to be named as they were not authorised to speak to the media. "There is an ongoing operation against the PKK in Iraq. There are certain targets in Syria after that is completed."

No group has claimed responsibility for the Istanbul bombing, and the PKK and the Kurdish-led Syrian Democratic Forces (SDF) have denied involvement.

Police have detained 50 people as part of an investigation into the bombing, Justice Minister Bekir Bozdag said. A suspected Syrian woman named Ahlam Albashir was detained early Monday morning.