India had warnings of a security threat days before two bombs went off in a market in Hyderabad, killing 16, according to the home minister.
Bombs planted on bicycles exploded in a major IT centre in India yesterday with 117 left wounded by the attack.
Home Minister Sushil Kumar Shinde said the government had been warned of an unspecified threat: "A general alert was given in the past two to three days to the whole country. And that's all."
The main political opposition in India, called for a one-day strike in Hyderabad to protest against the attack.
The Foreign Office minister Hugo Swire has said he is "appalled to hear of the bomb attacks in India."
It also advises British nationals to "exercise caution" since there is a "high threat from terrorism throughout India".
Police have begun investigating and collecting evidence at the sites of two explosions in Hyderabad, India.
A government minister said the bombs were loaded onto two bicycles around 150m apart.
This video shows the aftermath of two blasts in the southern Indian city of Hyderabad which killed at least 11 people.
Police can be seen trying to collect evidence in plastic bags among the crowd.
- July 2011 - 26 killed by three bombs in Mumbai
- February 2010 - 16 killed in Pune when a package explodes at a German Bakery popular with tourists
- November 2008 - 166 killed in Mumbai when gunmen open fire at sites across the city
- September 2008 - Five bombs in busy shopping areas of Delhi kill 25 people
- August 2007 - At least 38 killed in three blasts at a street-side food stall and amusement park in Hyderabad. Police defused 19 more bombs.
- July 2006 - 186 killed when seven bombs explode on Mumbai’s trains
- October 2005 - Three bombs explode in three Delhi markets killing 62 people
The blasts took place in a busy area of Hyderabad close to a large fruit and vegetable market, according to local reports.
India's Federal Home Minister Sushilkumar Shinde said the bombs were attached to two bicycles about 150m (500 feet) apart, the Associated Press reports.
He said eight people died in one explosion and three in the other.
India's Prime Minister Manmohan Singh has condemned the attacks on Hyderabad and appealed for calm in the city.
The two sites appear to be just across a busy road from each other in a heavy built-up area.