Rights groups have filed a lawsuit in a New York court to demand the release of two refugees in transit who have been detained at John F Kennedy airport.
Entry to the US for nationals of seven Muslim-majority countries has been stopped for 90 days by President Trump.
The exact implications of his order remain unclear. The US State Department has told the BBC it is working on the immediate implementation of the ban.
People fleeing Syria are banned until further notice.
The other countries affected are Iran, Iraq, Libya, Somalia, Sudan and Yemen.