Turkish authorities have detained 82 foreigners in Istanbul suspected of having links to the Islamic State group and planning to go to Syria, as Turkey's crackdown against the jihadist group widens.

Police officers have been conducting raids almost daily against IS cells across the country, with increasing intensity in the past few weeks.

The state-run Anadolu news agency said the suspects had previously been involved with IS fighters in "conflict zones", and were planning to try to reach Syria "in the coming days".

Separately, the privately owned Dogan news agency reported that nearly 800 alleged IS members had illegally crossed into Turkey from Syria, though it did not say over what period.

Police raided 14 addresses in Istanbul, and also detained 11 other suspects of Syrian origin in the southern city of Adana, Anadolu reported.

The detentions were reported a day after a series of anti-lS raids in Ankara during which at least 173 people were detained in operations conducted by 1,500 police officers.

Most of those detained were of Syrian origin, Dogan reported.

The agency added that authorities had carried out Thursday's raids over fears of an attack on November 10, the date on which Mustafa Kemal Ataturk, father of the modem Turkish republic, diedin 1938.

Dozens of people had already been detained in Ankara late last month, some of whom were suspected of planning an attack on Republic Day on October 29.

According to the interior ministry, around 450 suspects were detained on suspicion of helping or being in contact with IS in October.