The military travel ban was a key policy decision to rein in the influx of refugees and migrants that had surged into Europe following the September 11, 2001, attacks, which killed more than 3,000 people.
It was also designed to prevent a wave of terror attacks in Europe.
In 2017, it was extended to include some non-U.S. countries, such as Australia and New Zealand, where it had been imposed earlier.
The restrictions have been controversial from the start, with some critics claiming the move could limit freedom of movement and increase security risks.
On Monday, the government announced the military would be allowed to allow travellers to travel in some areas of the European Union, the United Kingdom and Canada without having to prove they were bona fide refugees or asylum seekers.
However, the military will still be prohibited from allowing non-resident military personnel to fly into the United States, the Pentagon said.
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