The country's top defence and nuclear scientists and major defence installatiions were Thursday given heightened security cover including deployment of Quick Reaction teams in the wake of Wednesday's suspected terror attack on Indian Institute of Sciences in Bangalore.

Officials said key Defence Research and Development Organisation scientists, including missile scientists in Delhi, Hyderbad, Pune, Kanpur, Gwalior and Bangalore had been also provided additional personal security.

Hours after unidentified gunmen struck at the Indian Institute of Science premises, top defence security officials held a meeting and Quick Reaction teams were deployed at Hindustan Aeronautics Limited, Aircraft Development Agency, Indian Air Force training command headquarters as well as at Yelhanka air base near Bangalore.

In the meeting, the security cover for top defence scientists came up for review and more personal armed security guards would be given to these eminent men, they said.

Security was also beefed up at vital DRDO and Bharat Dynamics limited establishments in Hyderabad.

"All major DRDO establishments, particularly missile, space and nuclear establishments have been provided with new stepped-up security ring," officials said.

The Indian Space Research Organisation has sounded a red alert at all its institutions across the country. Security was beefed up at the space agency's headquarters in Bangalore after the attack on scientists at IISc on Wednesday night.

Security was tightened at the premier Bhabha Atomic Research Centre in Mumbai, which houses the nation's nuclear assets and IIT in the suburban Powai.

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"We have given further instructions to our security officials at various points to be more alert," BARC Controller P Venugopalan told PTI in Mumbai.

In Hyderabad, where Prime Minister Manmohan Singh [Images] is scheduled to inaugurate the 93rd Indian Science Congress on January 3, security forces have been put on extra alert. President A P J Abdul Kalam will be addressing the Congress, which will be attended by over 100 scientists.

The terror attack in Bangalore has 'added a new dimension' to security at the Acharya N G Ranga Agricultural University, its venue, Indian Science Congress Association president I V Subba Rao told PTI from Hyderabad.

"We are taking extraordinary precaution at the venue and coordinating with the police and paramilitary forces to ensure foolproof security," he said.

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Additional forces have also been stationed at all scientific institutions, national laboratories and vital installations across the country