Four low intensity blasts within a span of 30 minutes rocked Pune on Wednesday evening when newly appointed home minister Sushil Kumar Shinde was to visit the city but later cancelled his plan.
No one died in the serial explosions but one person was injured.
The blasts took place in the heart of the city - on the crowded Jungli Maharaj Road commercial hub, known for its eateries and restaurants - between 7.45pm and 8.15pm.
City police chief Gulabrao Pol rejected the possibility of a terror attack but Union home secretary RK Singh said in Delhi that the terrorist angle could not be ruled out as the blasts were a "planned attack".
The Centre rushed teams of the National Investigation Agency and explosive experts to Pune to join the anti-terrorism squad of the Maharashtra Police.
The explosions took place less than an hour after Shinde was given his first briefing on the country's security situation. Shinde said it was only after an inquiry that the facts of the "low intensity blasts" would emerge.
As intelligence officials pointed out, Pune is a city where Indian Mujahideen (IM) operatives have been active.
Besides, LeT operative David Coleman Headley had done reccees of many locations in Pune, which is also home to two key IM operatives, Mohsin Chaudhry and Mansoor Asghar Peerbhoy.
The city was the venue of many IM meetings too.
The first blast was detonated at Bal Gandharva Rangmandir cultural centre, where the device was placed in a cake box.
This was followed by three successive blasts - one at a McDonald's outlet and two near Dena Bank and Garware Bridge - all on Jungli Mahal Road.
Two explosives were kept on a bicycle while another went off in a dustbin near McDonalds.
Top tweets from Pune:
Mahendra Palsule @Palsule: #Pune blasts very minor. Most didn't even hear them in crowded area. 1 with minor injuries. Be cautious, don't panic.
Sarang Brahme @Sarangbrahme: 5 minor blasts in #Pune (India). Low intensity but big enough to spread terror!
Vidyut @Vidyut: 6 #blasts #Pune now. One injury. Tells you that they are not big blasts. Be careful. Avoid crowded areas, don't panic.
Amit Paranjape @aparanjape: Now @abpmajha is reporting 4 blasts..4th one near Garware flyover Gymkhana. #Pune
We have still not got over the German Bakery blast and the fact that culprits roam free. An now JM Road! Too bad, too shocking.
JM road v v v crowded at this tym..adjacent FC road 10 tyms more crowded...80% of thm young students.
One bomb went off in injured man's bag | Role of IM, right wing outfit being probed | Shinde's tour to Pune was cancelled at last minute | Mumbai on high alert after blasts | Security enhanced in Delhi