Twelve people have been killed and more than 50 others injured in a series of explosions in the city of Ahmedabad in western India, according to officials.
On Saturday, there were 13 separate blasts across the city, which is the commercial capital of Gujarat state, said police sources.
The day before those blasts, there were seven almost simultaneous bombings in across the city of Bangalore.
Officials were saying that the blasts were “low-intensity” bombings, similar to those which occured in Bangalore, said Al Jazeera’s Todd Baer, reporting from New Delhi.
“The bombs, we are being told, were planted on bicycles and in lunch packs”, he said.
Many of the bombs were placed in busy areas of Ahmedabad, such as a railway station and a diamond market. Another device appeared to have been detonated on a bus.
The first explosion was reported on a bridge in Ahmedabad, at around 6:00pm (12:30 GMT). In 2002, bloody clashes between Hindus and Muslims took place on that bridge.
The attack has been condemned by the Indian prime minister, Mammohan Singh, who urged Ahmedabad residents to remain calm, said his office in New Delhi.
Sriprakash Jaiswal, a junior home minister, was critical that the attacks had come despite security being heightened after the Bangalore blasts.
He told reporters in New Delhi that “this is very unfortunate and we are surprised that despite a high security alert sounded yesterday after the bomb attacks in Bangalore, the blasts occurred today in Ahmedabad. We are shocked”.
“It seems there is a lack of co-ordination between [federal] intelligence agencies and people involved in the policing.”
“A small militant group” is suspected of being behind the attacks in Bangalore, said India’s home ministry.
“Special squads have been formed to find out who is behind the blasts. We have not got any conclusive leads yet”, M.R. Pujar, Bangalore’s additional commissioner of police, said on Saturday.
For previous attacks in India, Islamist groups in Pakistan and Bangladesh have been blamed.
“This seems to be within a very long established battle and we have been seeing such blasts in intervals of a few weeks to three months, almost regularly for the past three to four years, somewhere or other in the country”, said Ajai Sahni, a security analyst from India’s Institute of Conflict Management.
“One or a combination of a small group of terrorist organisations is in all probability involved in these blasts as well”, he told Al Jazeera.
“Controlling interests are the same, however the executing groups may or may not be the same, but the overall umbrella of organisations who are the handlers are basically the same group of Pakistan-based groups backed by the inter-service intelligence of Pakistan.”
“All past major incidents that we have seen have pointed to control on Pakistani soil and there is no reason to believe that they are not connected through one single objective”, said Mr Sahni.
At least 63 people have been killed and hundreds more injured in May, when eight bombs, many strapped to bicycles, were ripped through a crowded shopping area in the western city of Jaipur.