The official, who spoke on condition of anonymity due to restrictions on talking to the media, said Ankara chief public prosecutor's office had issued arrest warrants for 55 foreign nationals, as part of an investigation against the terrorist group, Anadolu Agency reported.

On Saturday, the police arrested 49 of the 55 suspects during operation in Ankara.

The official said some of the suspects were planning an attack on the country’s Republic Day celebration on Oct. 29.

Some of the suspects are also believed to have participated in armed conflicts abroad.