A low-intensity blast at a hospital in the tourist city of Agra injured at least three people on Saturday, a local police official said.
Television channels, citing sources, said the blast appeared to be a crude explosive device that had been placed under a chair at the reception area of the private hospital.
No one has claimed responsibility for the blast.
We are examining it. It is too early to talk about the nature of the blast, Brij Lal, special director general of the police in Uttar Pradesh, told Reuters.
Earlier, media reports said as many as eight people had been injured.
The explosion comes more than a week after a bomb, hidden in a briefcase, exploded outside the Delhi High Court, killing 15 people and injuring scores more.
The Islamist militant group Harkat-ul-Jihad Islami, or HuJI, has claimed responsibility for the Delhi attack and police have detained several people in Jammu and Kashmir in connection with the attack.
HuJI, an illegal organisation, is predominantly based in Pakistan and Bangladesh and is blamed for a number of attacks in the region, including attacks on India.