The nation was on Friday placed under high alert in the wake of the deadly serial blasts in Malegaon to check outbreak of communal tension and thwart fresh attacks.

Hours after terrorists struck the Muslim-dominated town in Maharashtra, the Union Home Ministry shot off a "detailed advisory" to all the states reminding them about the potential of such incidents "being exploited".

Security was stepped up at sensitive places around the country, including high-profile places of worship like Ayodhya, Mathura and Varanasi in Uttar Pradesh [Images], the old city in Delhil and Mumbai.

Additional police personnel were deployed in and around Jama Masjid and localities like Chandni Chowk in central Delhi [Images] as hundreds thronged the area on the occasion of Shab-e-barat, considered the holiest night under Islam.

Security has been beefed up at Hazrat Nizamuddin Dargah, Akshardam Temple and ISKCON temple in Delhi, where a tight vigil is also being maintained at crowded places including railway and bus stations, cinema halls and market places.

In Maharashtra, police have sealed all entry and exit points and tightened security at Siddhivinayak [Images] temple and Haji Ali in Mumbai, which has seen a wave of terror attacks barely two months ago.

The West Bengal government alerted all districts and directed the police and para-military forces to launch extensive patrolling in sensitive areas and step up security.

Security was also stepped up in sensitive places in Maharashtra's neighbouring states like Gujarat and Madhya Pradesh [Images].