CHICAGO (CBS) — In his first criticism of his successor since leaving office, former President Barack Obama said “American values are at stake” in the wake of President Donald Trump’s controversial travel ban.

Obama voiced support for protesters who have rallied across the nation to object to Trump’s executive order imposing a 90-day ban on travel to the U.S. by citizens of Iraq, Syria, Iran, Sudan, Libya, Somalia, and Yemen. The order also bars any refugees from entering the country for 120 days.

“President Obama is heartened by the level of engagement taking place in communities across the country. In his final official speech as President, he spoke about the important role of citizen and how all Americans have a responsibility to be the guardians of our democracy — not just during an election but every day,” Obama spokesman Kevin Lewis said in a statement.

Hundreds of protesters have rallied at O’Hare International Airport on Saturday and Sunday nights, after Trump signed the executive order. Another protest was planned for Monday night. Attorneys have been offering free legal help to people affected by the travel ban.

“Citizens exercising their Constitutional right to assemble, organize and have their voices heard by their elected officials is exactly what we expect to see when American values are at stake,” Obama’s statement said.

The former president also dismissed Trump’s claims that the current travel ban is similar the 2011 decision by Obama’s State Department to stop processing Iraq refugees for six months. Obama’s policy was not an outright ban on travel or visa applications.

“With regard to comparisons to President Obama’s foreign policy decisions, as we’ve heard before, the President fundamentally disagrees with the notion of discriminating against individuals because of their faith or religion,” Lewis said.

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