WASHINGTON (CNN) -- The Indian government has received information about threats "targeting airports on or around December 4 through December 6," the U.S. State Department said Friday.
The State Department mentioned the threat information in a travel alert it issued to U.S. citizens who plan to travel to India.
All major airports in India "have been placed on high alert following threats of airport attacks and hijacking of planes," the department's travel advisory said.
The warning urged Americans "traveling to or already in India" to "maintain a high level of vigilance and ... take appropriate steps to increase their security awareness."
Terrorist attacks in Mumbai on November 26 killed nearly 180 people.