“It’s very, very unusual to do a blanket revocation of everyone’s visa,” said Susan Cohen, an immigration attorney at Mintz Levin in Boston. “The thing that’s particularly distressing about this letter is that it doesn’t mirror the executive order.”

Zachary Nightingale, a San Francisco immigration lawyer said: “If all visas are cancelled then in the future everyone who had one will have to reapply. This is different than ‘no one can enter for 90 days.’”

Lawyers around the country are scrambling to get clarification. The confusion centers on what the letter means by the phrase “provisionally revoke.”

“Will visas automatically be reinstated? Or do you have to go back to the embassy and re-apply?” asks Denyse Sabagh, the head of the immigration practice at Duane Morris in Washington.

It is not a minor detail. In one case ProPublica reported last week, it took over five years for a young Yemeni girl with U.S. citizen parents to secure an immigrant visa.