A minor blast took place here on Friday near the Mount Carmel College following which the route of Home Minister Amit Shah, who was on his way to Bengaluru from Chikkaballapur after attending a programme, was changed, officials said.

An official said the blast took place at a drain -- ahead of the Union Minister's arrival here, creating panic in the Vasanthnagar locality. Shah was supposed to pass through that area.

The police said the blast took place at around 4.30 p.m. following which a power chamber that was installed nearby broke into pieces

Bengaluru Police Commissioner Kamal Pant rushed to the spot for an inspection.

After the blast, a thick smoke emerged due to the short circuit in the underground electric cable, the police said. The vehicular movement was blocked until the inspection was done.

Officials said Amit Shah's route was changed following the incident as miscreants issuing threat to Prime Minister Narendra Modi has also come to light.

The blast has also led to concerns over the safety and security of the Union Minister.

The police have taken up the incident seriously, and are conducting a probe into it, an official said.