The Uttar Pradesh Police on Wednesday said the youth killed in an anti-terror operation here on Wednesday morning and his five arrested associates were "self radicalised" and were trying to build an Islamic State Khorasan module in the city.

The Uttar Pradesh Police statement came hours after its Anti Terrorism Squad (ATS) killed Saifullah, a resident of Manohar Nagar in Kanpur, here in an 11-hour-long gunfight in Thakurganj's Haji colony.

"Safullah and his five associates are self radicalised. They did not get financial support from outside (foreign country). They generated it from their own property. They were trying to build an IS Khorasan module here and planning for terror attacks at several places," Additional Director General (Law and Order) Daljit Chaudhary said at a press conference here.

Chaudhary said they tried to trigger low intensity blasts but failed and the Uttar Pradesh ATS killed Safullah and busted the module before they managed to succeed in their motive.

The officer said they got inputs from several agencies about the likely presence of terror suspects in Lucknow, Kanpur and Etawah after an explosion took place on a train in Madhya Pradesh on Tuesday in which eight people were injured.

The gun battle broke out around 4 p.m. on Tuesday in Lucknow and continued for over 11 hours, concluding early on Wednesday with the killing of Safullah.

Two of the terror suspects, Mohammad Faisal Khan and Fakhre Alam, were arrested from their native places in Kanpur and Etawah.

Faisal's elder brother Mohammad Imran was also arrested from Unnao in the operation, said the officer, adding they are currently being interrogated by the ATS.

"Two others detained by the ATS in Kanpur were set free by a mob but we know their residential information and hope to catch them soon," the officer said.

He said that Atish Muzaffar, Danish Akhtar and Sayed Mir Hussain were arrested by Madhya Pradesh Police. Muzaffar is the mastermind of the module, he added.

The police official's statement that the men were not linked to the Islamic State comes as Madhya Pradesh Chief Minister Shivraj Singh Chouhan on Wednesday said in Bhopal that those behind the Bhopal-Ujjain passenger train bomb blast had suspected Islamic State (IS) links.

Chouhan also revealed that the explosion was caused by a pipe bomb, whose pictures were sent to Syria through their mobile phones. A timer was also used in the bomb.

"The terrorists planted pipe bombs in the Bhopal-Ujjain passenger train and have links to the IS and we have proof. The explosives discovered have IS markings," he told reporters.