Agra, Sep 18 (IANS): Uttar Pradesh Police were yet to confirm Sunday morning whether a low-intensity blast at a private hospital here was a terror strike, a day after it left at least four people injured.

"It is still inconclusive. All angles are being probed by the Special Task Force (STF) and anti-terrorist squad in connection with the blast," Inspector General of Police (Agra Zone) P.K. Tiwari told reporters.

According to police sources, the state police in its report sent to the union home ministry late Saturday said they were trying to ascertain whether the blast was a terror strike or an attack due to some business rivalry as there were a number of private hospitals near Jai Hospital where the explosion took place Saturday evening.

"We are working on the evidence gathered from the site. Everything will be shared with the media once we have confirmed reports about the nature of the explosives used," Special Director General of Police Brij Lal said here.

A.K. Mishra, station house officer (SHO) of the Hari Parwat police station, which has jurisdiction of the blast site, told IANS: "No one has been detained in connection with the blast."

"Two of the four injured have been discharged from hospital," he added.

The explosion took place around 5.30 p.m. at the reception area of Jai Hospital, situated on a service lane of National Highway-2, barely 2.5 km away from the Taj Mahal, a declared terror target frequented by thousands of tourists -- domestic and foreign.

Security at the 17th century monument and other places has been beefed up in the city.

"It was a low-intensity explosion. It appears the explosive was kept under a seat at the hospital's reception area," Uttar Pradesh's Special Director General of Police Brij Lal had told IANS in Lucknow.

In New Delhi, union Home Secretary R.K. Singh said reports indicated wires and battery parts were found at the blast spot.