Trump on Friday put a four-month hold on allowing refugees into the United States and temporarily barred travellers from Syria and six other Muslim-majority countries, saying the moves would help protect Americans from terrorist attacks.
The six passengers, bound for John F. Kennedy International Airport, were prevented from boarding Egypt Air Flight 985 at Cairo airport despite holding valid immigration visas, the sources said, Reuters reported.
The five Iraqis had arrived in transit from Erbil and were being held at the airport until they could be re-boarded on flights back to Iraq, whereas the Yemeni passenger had arrived at the airport from elsewhere in Cairo, they added.
Trump halted the entry of travellers from Syria, Iraq, Iran, Sudan, Libya, Somalia and Yemen for at least 90 days, saying his administration needed time to develop more stringent screening procedures for refugees, immigrants and other visitors.
A UN refugee agency spokesman said it was not yet known whether the six travellers had been granted visas earlier under the US refugee programme.