India intensified security at airports and other public places across the country Saturday, a day after the U.S. Embassy warned that foreign militants, possibly Al Qaeda terrorists, could be planning bomb attacks.

A U.S. Embassy e-mail sent to Americans in India on Friday said New Delhi and Bombay were the likely targets of the alleged plot, and the attacks were believed to be planned around Independence Day celebrations on Aug. 15.

The warning came a day after British police said they had thwarted another terrorist plan, possibly just days away, to blow up U.S.-bound jetliners over the Atlantic and kill thousands using concealed liquid explosives.

Countrywatch: India

India's Civil Aviation Ministry advised passengers to reach airports well in advance because of the new security requirements, the Press Trust of India reported Saturday.

"A new threat has emerged from the unearthing of the terror plot in London ... we have taken note of this fact," Civil Aviation Secretary Ajay Prasad was quoted as saying.

Only one piece of hand baggage will be allowed on domestic flights, and no carry-on bags will be permitted for flights to Britain, Prasad said. Liquids, including shampoos, beverages, toothpaste, and lotions, were banned from all flights.

The U.S. Embassy's warning for India said the "likely targets include major airports, key central Indian government offices, and major gathering places such as hotels and markets." It urged Americans to maintain a low profile and be alert between Aug. 11 and Aug. 16.

Al Qaeda has not been blamed for any previous attacks in India, and Usama bin Laden's network isn't known to have any direct presence in the country.

But Indian National Security Adviser M.K. Narayanan said the Pakistan-based group Lashkar-e-Tayyaba was the "most visible manifestation of Al Qaeda in India," according to the private New Delhi Television channel.

More than a dozen Islamic rebel groups have been fighting security forces in India's portion of Kashmir for the region's independence, or its merger with mostly Muslim Pakistan.

On July 11, seven bombs exploded on trains in Bombay, killing 207 people. Indian officials suspect the attacks were the work of homegrown and Pakistani Islamic militants.