President Trump signed an executive order Wednesday claiming to end the separation of children from their parents at the border, by jailing them together while their legal cases wind through the courts. The order does not say where the families will be detained, or whether children will continue to be separated from their parents until the facilities are ready.

President Trump: “We want security for our country. The Republicans want security and insist on security for our country and we will have that. At the same time we have compassion. We want to keep families together. It’s very important. I’ll be signing something in a little while that’s going to do that.”

Critics warn the order will lead to the indefinite detention of entire families. And the Trump administration has so far not outlined any plans for reuniting children already separated from their families. At least 2,300 children have been separated since Attorney General Jeff Sessions announced a “zero tolerance” policy in April, with The Intercept reporting the number jailed since last October could be as high as 3,700.

American Airlines and United Airlines have asked the Trump administration to stop transporting immigrant children who have been separated from their families aboard their company’s planes. American Airlines said in a statement, “We have no desire to be associated with separating families, or worse, to profit from it.” And United Airlines CEO Oscar Munoz said, “Our company’s shared purpose is to connect people and unite the world. This policy and its impact on thousands of children is in deep conflict with that mission and we want no part of it.”