Raids were conducted in Mumbra, Jalandhar, Narkatiaganj, Bijnor and Muzaffarnagar.
Four suspected ISIS 'sympathisers' were arrested while several others were detained during joint anti-terror raids on Thursday in four states for plotting major terror strikes, a senior police officer said.
The Uttar Pradesh Anti-Terorism Squad (ATS) in coordination with police agencies of five other states carried out the operation on the basis of a tip-off from central intelligence agencies, Uttar Pradesh Additional Director General of Police Daljeet Singh Chawdhary said.
The raids were conducted in the early hours in Mumbra (Maharashtra), Jalandhar (Punjab), Narkatiaganj (Bihar), and Bijnor and Muzaffarnagar (both in Uttar Pradesh) by joint teams of Delhi Special Cell, Anti-Terorism Squads (ATS) of Uttar Pradesh and Maharashtra and Crime Investigation Cell of Andhra Pradesh.
Punjab and Bihar Police also provided assistance in the operation.
Mufti Faizan, Tanveer, Nazim Shamshad Ahmed and Muzammil were arrested from Bijnor, Mumbra and Jalandhar.
The ADGP said the raiding team picked nine youths -- aged between 18 and 26 -- from different locations and arrested four of them on charge of hatching terror conspiracies.
"The arrested youths were planning terror attacks in different cities. Others detained are being questioned. They are self-motivated and misguided. They can be brought back to the mainstream after counselling," Mr Chawdhary said.
The officer said the suspected ISIS sympathisers were in touch with each other on the Internet.
He said the state ATS got inputs about a terror group enrolling new members in Uttar Pradesh, Mumbai, Punjab and Bihar for carrying out terror strikes in the future.
Mr Chawdhary said investigations revealed that one of them wanted to finance the group and they were continuously communicating with each other about carrying some major strike in the near future.
The officer ruled out link between those arrested on Thursday with a suspected terrorist killed in an encounter in Uttar Pradesh capital Lucknow in March.
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