The U.S. Embassy in Kabul warned Monday it has received reports that militants plan to kidnap an American and other Europeans working for an NGO in Afghanistan.

The “emergency message” from the embassy said:

“The U.S. Embassy in Kabul has received reports that as of early January 2016 an unspecified group of militants plan to kidnap an unidentified American and unidentified Europeans who are employees of an unidentified non-governmental organization (NGO) in Nangarhar Province, Afghanistan.”

The notice did not identify the individuals who may be at risk, or the non-governmental organization (NGO) in question. The notice said the embassy does not have any further information on the “timing, target, location, or method of any planned kidnappings.”

The only other detail provided is that the employees in question “reportedly travel from Kabul City, Kabul Province, Afghanistan, to Nangarhar Province at unspecified intervals and possibly serve in an advisory role to the NGO.”

The message comes at a time of heightened alert in Afghanistan, where threats from the Taliban and other groups continue to rise.

The embassy reminded Americans that an official travel warning urges U.S. citizens not to travel in the country.

“The security situation in Afghanistan is extremely unstable, and the threat to all U.S. citizens in Afghanistan remains critical. U.S. citizens currently visiting or residing in Afghanistan may wish to consider departing,” the embassy said. “The Embassy strongly urges U.S. citizens who decide to remain in Afghanistan to review your personal security plans, take appropriate steps to enhance your personal safety, remain aware of your surroundings, monitor local media for updates, and maintain a high level of vigilance.”