The NIA, during its probe, found that the accused were conspiring to carry out terror acts in Punjab.
A charge sheet was filed in a special NIA court in Mohali on Thursday against four alleged Babbar Khalsa International terrorists for planning and conspiring to carry out terror acts in Punjab, officials said.
The accused have been identified as Kulwinderjit Singh, alias Khanpuria, of Ludhiana, Ravinderpal Singh, alias Ravi, of Moga, Jagdev Singh, alias Sonu, of Fatehgarh Sahib in Punjab and Harcharan Singh of Nihal Vihar in Delhi, they said.
The Punjab Police had arrested Ravinderpal and Jagdev in May this year. The accused are allegedly associated with the Babbar Khalsa International, a banned terrorist group, the officials added.
The NIA, during its probe, found that Kulwinderjit was the chief conspirator and had planned a planned terror strike, they said. The accused wanted to carry out serial blasts in public spaces, the officials added.
They further said Kulwinderjit and his associates were allegedly planning and targeting a few places in Punjab for terror attacks, adding that the accused had even done a reconnaissance of the people and places they wanted to attack by way of explosions.
The NIA believes that the accused aimed to disturb the law and order situation in Punjab and revive terrorism in the state, the officials said.
According to the agency, the accused had allegedly raised funds and arranged firearms and ammunition to carry out terror acts in the state. The electronic items seized from them had photos and videos used in reconnaissance.
The NIA officials said Kulwinderjit is suspected to have fled to Malaysia in January this year and has been operating the network from there.
"Kulwinderjit is absconding and as per available information, he is in Malaysia. The NIA has got a Look Out Circular issued against him in this case," a senior NIA officer told PTI.
The NIA is also probing a fifth accused in case -- Nishan Singh, alias Poonia.