New Dehli, India (CNN) -- India has stepped up anti-hijacking measures and ordered the deployment of air marshals as part of a security alert, officials said Friday.
P.N. Sukul, joint secretary for India's Ministry of Civil Aviation, said the alert was based on intelligence indicating that terror groups were planning an attack involving a flight from a South Asian country.
The threat might be aimed at one of the flights operating in a member country of the South Asian Association for Regional Cooperation or in Myanmar, formerly Burma, he said. The association members besides India are Nepal, Bhutan, Bangladesh, Sri Lanka, Maldives and Pakistan.
Sukul wouldn't elaborate further.
The alert, issued by the Civil Aviation Ministry issued to airports and airlines, directs "the stepping up of security arrangements at all concerned airports and airlines following inputs received from security agencies as well as the Ministry of Home Affairs."
"The level of security to counter threat perception has been upgraded, and all necessary measures have been undertaken by the agencies in charge of civil aviation security, including strengthening of anti-hijacking measures," the alert says.
Air marshals also will be deployed on certain flights, the ministry said.
Ragini Chopra, vice president of corporate communications for Jet Airways, India's largest private carrier, told CNN, that Jet "will put into effect any security measure specified by the government as well as their own security measures."
Air India told the Indian Express newspaper that it also was beefing up security.
The precautions come ahead of Republic Day on January 26, which marks India's adoption of a republican constitution after independence from Britain.
The alert was based on input from security agencies and the home ministry, Indian civil aviation authorities said.
In December 1999, hijackers commandeered an Indian airliner with more than 150 passengers, forcing pilots to fly to Kandahar, Afghanistan. It had been flying from Kathmandu, Nepal, to New Delhi.
The eight-day drama ended when India freed three jailed Kashmiri militants.
CNN's Harmeet Shah Singh, Bharati Naik and Paula Newton contributed to this report.