Truck owners and truck rental agencies are being warned to remain "vigilant" about an uptick in "ramming attacks" by terrorists who use vehicles to kill, NBC News reported.
An unclassified Transportation Security Administration report obtained by NBC News warns owners, operators and rental agencies to protect themselves from theft. Areas where large numbers of people congregate, such as parades or entertainment venues, are particularly vulnerable locations, according to a study of the attacks.
The report says that in the past three years, at least 173 people have been killed and more than 700 wounded in 17 ramming attacks worldwide. Thirteen of those attacks resulted in fatalities.
Vehicle owners are urged to report theft or other suspicious activities, such as attempts to reinforce the front of the vehicle with metal plates, immediately, the report says.