"Our operations are continuing. The number of those detained so far has risen to seven," Efkan Ala told Turkish ambassadors gathered in Ankara.

He did not give any details about the two new detentions.

A 28-year-old Syrian member of IS blew himself up Tuesday in Sultanahmet Square, home to Turkey's most visited historic sites, including the Ottoman-era Blue Mosque and the Hagia Sophia, a former Byzantine church that was turned into a mosque before later becoming a museum.

Authorities said the bomber, identified as Nabil Fadli, had recently entered Turkey from Syria but was not on Turkey's watch list of suspected militants.

The blast left 15 people wounded, most of them Germans.

Turkish security forces over the last few days also rounded up over 70 suspected IS members across the country, but it was not clear if any were directly connected to the Istanbul attack.

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