U.S. President Donald Trump’s latest travel ban is “chaotic” and legally problematic, an immigration lawyer told BNN.

Trump’s executive order on immigration bars nationals of seven Muslim-majority countries including Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen from entering the United States for 90 days, and suspends the American refugee program for 120 days.

In wake of the ban, there has been mayhem at airports, which has largely been fuelled by confusion of whether green cards and dual-citizenships were included.

“There’s a lot of chaos right now. Nobody really knows what to make of any of it,” Joel Sandaluk, immigration lawyer at Mamann Sandaluk & Kingwell, said in an interview Monday.

“Officers don’t really know what’s expected of them. The White House hasn’t been clear about what’s going on and the courts are obviously taking this entire matter into their control.”

Sandaluk said many portions of the travel ban are illegal, and have since been suspended, calling the order “very vaguely drafted.”

The main legal issue with the travel ban, according to Sandaluk, is it disputes the U.S. constitution.

“The major problem is that it deprives people from the right to liberty, without the right to a fair hearing,” Sandaluk said. “That’s something that’s constitutionally barred from the United States.”