The squad has recovered fake Aadhar cards from them, manufactured from fake identity and address---for which they were arrested.
Asim Arun, IG, ATS, told ANI that the ATS team arrested the three from Lucknow's Charbagh Railway Station on Thursday.
The three arrested, identified as Mohammad Imran, Rajiduddin and Mohammad Firdaus, are real brothers and residents of Jessore District of Bangladesh.
The arrested were later on produced before the court.
The UP ATS had earlier arrested Ansarullah Bangla Team's militant Bangladeshi Abdullah al-Mamun from Kutesera area of Muzaffarnagar on August 5.
After interrogating Abdullah, his other colleagues also came to light in the inquiry, whose search was initiated on September 12 and for which Deoband Madrasasas were also questioned.
Later on, it came into notice that three boys (a teacher and his two brothers) have fled from a Deoband madrasa.
The three absconding were later caught and taken off the Howrah Amritsar Express from the Lucknow Railway Station and were quizzed.
They then revealed their identity as Bangladeshi nationals and told that they have been living illegally in India.
ATS DSP Manish Sonkar will further interrogate the arrested and will inquire their affiliation with any terrorist organisation and the reason they fled Deoband.
Ansarullah Bangla Team is an Islamic extremist group in Bangladesh which is inspired by Al Qaeda.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)