New Dehli  - Security was tight at major Indian airports Friday after a security scare at New Dehli's international airport, where witnesses erroneously reported a night-time shootout.

According to local media, several sharp sounds caused reports of shots being fired, but a police search found no evidence of an attack. While normal operations resumed, the already tight security measures at Indira-Ghandi International Airports were tightened further.

India's main airports at New Dehli, Bangalore and Chennai were put on high terror alert Thursday following warnings from intelligence agencies, the Civil Aviation Ministry said.

An email to officials at the Delhi airport warned of hijacking and terror strikes from the Deccan Mujahideen between Wednesday and Sunday, IANS news agency reported citing official sources.

A ministry official said she was not aware of the mail or a hijack threat as reported by some news channels.

There is usually a high alert at major government installations across India on December 6. On that day in 1992, Hindu fanatics pulled down the medieval Babri mosque in the northern city of Ayodhya, triggering sectarian riots that killed more than 1,000 people.

The warning comes little more than one week after a more than 170 people were killed in a terror spree in the western Indian city of Mumbai. The attacks also raised tensions with India's nuclear-armed neighbour Pakistan, as India's govermnent sees Pakistan-based groups responsible for the carnage.

In a visit to both countries on Wednesday and Thursday, US Secretary of State Condoleezza Rice urged Delhi and Islamabad to show restraint.

Pakistan's President Asif Ali Zardari rejected any involvement of his government in the attack, saying non-state actors were responsible, but "take action against any Pakistani elements involved in the attacks." (dpa)