"The questioning of Syed Maqbool and Imran Khan is continuing," a senior NIA officer said even as he denied reports being carried by TV channels that two more suspects were picked up by the agency.
"No one else apart from the two IM operatives (Maqbool and Imran) are being questioned," he said.
As part of questioning, Maqbool and Imran were also taken to the blast sites, sources said.
Earlier, a Delhi court had granted NIA permission to take the custody of the duo for questioning till March 9. They were brought here from Tihar jail.
Also Read
According to the NIA, the blasts took place at the instructions of IM's Pakistan-based founder Riyaz Bhatkal and the duo's interrogation would help in unearthing the plan envisaged by him.
The blasts in Hyderabad were triggered by powerful IEDs planted near Konark and Venkatadiri theatres in Dilsukhnagar.
Andhra Pradesh Police, who are probing the blasts case, has formed 15 teams to carry out the investigation.