The explosion which occurred at 5:45 PM broke the windowpanes in the reception area where 10 to 15 people were seated in steel chairs. Several patients were evacuated from the hospital and police cordoned off the entire area and conducted a combing operation.
The Uttar Pradesh Anti-Terror Squad sources have told NDTV that an Improvised Explosive Device (IED) was used for the blast.
A battery and wires have also been recovered from the blast site, sources add.
Earlier, P K Tiwari, the Inspector General of Police, Agra, said preliminary investigations suggested the use of a crude bomb, which was kept under a seat in the reception area.
Tiwari ruled out the possibility of tiffin boxes being used in the explosion, which created panic among patients and medical personnel at the hospital. He added that the injuries sustained were not of a serious nature and all of them were being treated in the hospital itself.
The Home Ministry has said that information on the blast is being collected. A post-blast team of the National Security Guard (NSG) will leave soon for Agra.
The blast comes just days after a bomb, kept inside a briefcase, exploded at the Delhi High Court, claiming 15 lives.
(With agency inputs)