ISTANBUL — Turkey has identified the gunman in the Istanbul nightclub massacre, the foreign minister said Wednesday, as the president vowed that the country won’t surrender to terrorists or become divided.

The gunman, who killed 39 people during New Year’s celebrations at the Reina club, is still at large. But Foreign Minister Mevlut Cavusoglu said authorities had identified the man, without providing details.

“The identity of the person who carried out the attack on the Reina nightclub has been established,” Cavusoglu told state-run news agency Anadolu in a live televised interview.

Turkish police, meanwhile, detained 20 suspected Islamic State group militants, including 11 women, believed to be linked to the attack, Anadolu reported. The operation was launched in the Aegean port city of Izmir.

It said the suspects were from the largely Muslim Russian republic of Dagestan, from China’s Muslim Uighur minority and from Syria. It said they are thought to have lived with the nightclub attacker.

IS has claimed responsibility for the attack, which also wounded nearly 70 people. Of those killed, 27 were foreigners, many from the Middle East. Islamic State said a “soldier of the caliphate” had carried out the mass shooting to avenge Turkish military operations against IS in northern Syria.