Three suspected ISIS supporters were detained in Tamil Nadu's Coimbatore (Representational)

Three suspected ISIS supporters were detained in Tamil Nadu's Coimbatore Thursday by police for interrogation over alleged conspiracy to carry out attacks in the city, a day after the NIA arrested the terror outfit's Tamil Nadu module mastermind following searches.

Police said they carried out searches at the houses of Mohamed Hussain, Shahjahan and Sheik Safiullah and seized "incriminating" documents and digital devices.

"The three persons are being interrogated regarding the incriminating materials seized during the search," a police release said.

The seized devices included cellphones, SIM cards, computer hard disks, bank account documents, pen drives, memory cards.

It said the searches against the three were carried out following information that they were "staunch supporters" of ISIS and have been propagating the terrorist organisation's ideology in social media.

They were also supporters of Zahran Hashim, mastermind of Sri Lanka Easter Sunday suicide bombings, and had praised his act besides conspiring to stage terror attacks, the release said.

A case under section 18, 38 and 39 of Unlawful Activities Prevention Act 1967 had been registered against the three, it added.

The police action came after the National Investigation Agency Wednesday carried out raids at seven locations and arrested Mohammed Azarudeen, the alleged mastermind of ISIS Tamil Nadu module who was a Facebook friend of Hashim.

A report from Kochi said Azarudeen was produced before the NIA court there and it remanded him to judicial custody Thursday.

During the searches in Coimbatore, the NIA had seized digital devices, including 14 mobile phones, 29 SIM cards, a large number of incriminating documents and a few pamphlets of Popular Front of India and Social Democratic of India, both under the scanner of security agencies.

The agency had received the information that the accused persons and their associates were allegedly propagating the ideology of proscribed terrorist organisation ISIS on social media with the intention of recruiting vulnerable youth into the group for carrying out terrorist attacks in south India, especially in Kerala and Tamil Nadu, the NIA said.

The intention of those detained by NIA was to recruit vulnerable youth into the ISIS or Daish for carrying out terrorist attacks in south India, especially in Kerala and Tamil Nadu, it had said in a release last night.

Azarudeen was the leader of the module and has been maintaining a Facebook page ''KhilafahGFX'', through which he had been propagating the ideology of ISIS, it said.

The NIA has alleged that Azarudeen has been a Facebook friend of suicide bomber Zahran Hashim and other members of the module have also been sharing radical contents attributed to Hashim, over the social media.

The ISIS had claimed responsibility for the serial bombings in Sri Lanka on April 21 in which around nine suicide bombers were involved.