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.
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Cloud and outbreaks of rain will ease away eastwards during the morning, clearing the east coast around midday with sunny spells developing.
Police and emergency services are attending the scene.
Rebel-held east remains at risk while the pumping station supplying the western part of the city is once again in operation.