Delhi has been put on high alert and security beefed up at all important buildings and markets following two blasts in Hyderabad, officials said.

"The city is on high alert and security has been stepped up. The number of armed security personnel at all important buildings and markets has been increased," a senior police officer said.

"Patrolling has been intensified as well," he added.

At least 10 people were killed and 50 injured in the twin blasts near two theatres in Dilsukhnagar, a busy commercial area in the southern part of Hyderabad, about 15km from the heart of the city.