Additional Sessions Judge Reetesh Singh allowed the cops to further quiz the accused persons -- Mohd Sajid, Shakir and Sameer -- till May 24 after the police told the court that their custody was required to unearth the larger conspiracy.
The Delhi Polcie, in its application, sought 15 days of custody of the accused while submitting before the court that it has recovered a number of 'WhatsApp' messages which need to be verified and the accused were required to be confronted with some 'Facebook' datas.
The court had earlier sent the accused to 10-day police custody after investigators submitted that their custodial interrogation was required to crack their Delhi module.
Delhi Police had detained around 10 more persons suspected to be linked with a terror outfit planning an attack in the city and recovered explosives from their possession after a series of overnight raids in the national capital and neighbouring states.
Special Cell teams had conducted raids in Delhi and UP in a joint operation of Delhi Police and a central intelligence agency.
All the three accused were suspected to be members of a sleeper unit of a terror outfit, planning an attack in the national capital and other cities, police said.