Updated

Sen. Cory Booker fanned the flames of those protesting what they say is a “Muslim ban” early Sunday, with Booker telling demonstrators at Dulles International Airport that the people denied entry were “singled out” because of how they “decided to pray.”

Booker, D-N.J., has been one of the loudest voices of dissent against President Trump’s early agenda, even taking the unprecedented step of testifying against the confirmation of fellow Sen. Jeff Sessions for attorney general. A prospective 2020 White House contender, Booker on Twitter said he also planned to be at Newark Airport later Sunday.

“We must stand as witness, we must stand as resistors, we must stand in opposition to what others are trying to do to violate the law, the constitution and our values,” Booker told those gathered at Dulles in Washington, D.C.

But Booker saved the most provocative part for his finale, positioning Trump’s executive order as an outright ban on Muslims – something Trump vociferously has denied of the order, which largely targets “countries of concern” that were selected by former President Obama’s Department of Homeland Security.

“It’s not a Muslim ban,” Trump said Saturday.

Booker disagreed.

“But I’m telling you right now that tomorrow more people will be trying to come into our country,” Booker said. “And what frustrates me is that they are being singled out now simply because of how they have decided to pray and their country of origin. That has to be unacceptable to every American.”

Booker took to his Twitter account shortly after the speech, replying to those who both attacked and supported his stance. He pinned a tweet to the top of his account saying, “President Trump’s fundamentally un-American executive order today stands in painful contrast to our ideals.”