March 19 (UPI) -- The government of Germany on Wednesday updated travel guidance for people traveling to the United States after three of its citizens were detained in an attempt to enter "the land of the free."
Germany's foreign office warned German citizens that more strict immigration policies under U.S. President Donald Trump may land travelers in detention or face a possibility of deportation.
However, it stopped short of issuing a formal warning.
Germany, which is the European Union's largest economy, also warned that even minor infractions could trigger deportation or ban on any future entry into the United States.
"A criminal conviction in the United States, false information regarding the purpose of stay, or even a slight overstay of the visa upon entry or exit can lead to arrest, detention, and deportation upon entry or exit," according to the German Foreign Office advisory.
It arrived as the ministry said Monday it was investigating the case of three German citizens who had been denied entry into the United States and were put in a detention facility while attempting to enter.
"The Federal Foreign Office is aware of three cases in which German citizens were unable to enter the United States and were placed in deportation detention upon entry," stated a foreign ministry spokesperson.
According to the U.S. embassy in Berlin, German citizens with a valid tourist visa to the United States are generally allowed to travel visa-free for up to 90 days.
Among those arbitrarily detained by American officials in separate cases were a 34-year-old legal permanent U.S. resident at a Boston airport before he was transferred to a Rhode Island facility.
The German national, Fabian Schmidt, was "violently interrogated" and stripped naked before he was forced into a cold shower, according to his mother, Astrid Senior. The other two were a 29-year-old female tattoo artist Jessica Brosche and a 25-year-old Lucas Sielaff.
It came as a strike at Germany's Hamburg Airport a little more than a week ago left all outgoing flights canceled with more airports that were likely to be affected.