Turkish authorities have placed seven more suspects under arrest over the triple suicide bombings at Istanbul’s main airport last month.

Turkish authorities have placed seven more suspects under arrest over the triple suicide bombings at Istanbul's main airport last month, bringing to 37 the number charged over the attack, media reports said Monday.

Forty-seven people were killed and 200 wounded in the June 28 bombings and gun attacks on Ataturk International Airport which the Turkish authorities blamed on Takkfiri ISIL group.

Seven suspects, all foreigners, were placed under arrest by an Istanbul court on Sunday following their detention last week, the Dogan news agency reported, adding to the 30 already remanded in custody.

The seven, like the other suspects, have been charged with "membership of a terror group" and assisting in murder. No further details were given on their citizenship.

Authorities have said that a number of citizens of ex-USSR republics are among the suspects, raising concerns over the threat to Turkey from Takfiri militancy in the Central Asia and the Northern Caucasus.

Turkish media have identified the strike's organizer as Akhmed Chatayev, a one-armed Chechen who leads an ISIL cell in Istanbul and allegedly masterminded other deadly attacks in the city.

Reports have said that the three suicide bombers were from the ex-Soviet Central Asian republics of Kyrgyzstan and Uzbekistan as well as Russia's Caucasus region of Dagestan.

Turkey has been rocked by a series of attacks over the past year, blamed on both ISIL terrorists and Kurdish rebels, dealing a heavy blow to its key tourism industry.