The official said that Naeem has been involved in the supply of weapons to the accused persons in the case, who were allegedly planning to attack some political personalities and security establishments as well as crowded places in Delhi and the National Capital Region.
On December 26, the NIA arrested 10 persons, including group leader Mufti Mohammad Suhail, after the counter-terror probe agency carried out searches at 17 places -- six in east Delhi's Jafarabad area, six in Amroha, two each in Lucknow and Hapur and one in Meerut.
The agency also seized a country-made rocket launcher, 12 pistols, 112 alarm clocks, 100 mobile phones, 135 SIM cards, several laptops and various electronic gadgets, besides 150 rounds of ammunition.
After the arrest of the 10 persons, the NIA also carried out follow-up searches in several cities of Uttar Pradesh to identify more suspects of the new IS module.
It also rounded up many people for questioning.
The NIA also seized 25 kg of explosive material, such as potassium nitrate, ammonium nitrate, sulphur, sugar material paste, mobile phone circuits, batteries, 51 pipes, remote control car triggering switch, wireless digital doorbell for remote switch, steel containers, electric wires, knife, sword, IS-related literature and Rs 7.5 lakh in cash.
All the arrested members of 'Harkat-ul-Harb-e-Islam' are in NIA custody.
The agency had registered a case on December 20 under several sections of the Indian Penal Code, the Explosive Substances Act and the Unlawful Activities (Prevention) Act.