President Trump said he warned Turkey it would face economic sanctions if it does not protect religious minorities in northern Syria while it conducts military operations there.

The president’s decision earlier this week to withdraw American troops from northern Syria, thereby opening the region to an invasion by Turkey, was met with consternation among Trump’s usually loyal evangelical supporters. Trump attempted to assuage their fears that Syria’s minority Christian community would suffer increased persecution as Turkish forces clash with other actors in the region.

“I have made clear to Turkey that if they do not meet their commitments, including the protection of religious minorities … we will impose very swift, strong, and severe economic sanctions,” said Trump at the Values Voter Summit, a gathering of social conservatives in Washington, D.C., on Saturday.

The president also announced he directed $50 million to aid Christians and other religious minorities in Syria earlier this week.

“With one clear voice, the United States of America condemns the persecution of Christians, and we pledge our support to Christian communities everywhere suffering under the brutal heel of oppression and violence," he said.

[Also read: Trump appearing before evangelicals as Turkey policy imperils Kurd-protected Christians]

While the Trump administration has been committed to promoting religious freedom, his decision to withdraw from northern Syria appeared to undermine that commitment in the eyes of some evangelical leaders.

Tony Perkins, president of the Family Research Council, a nonprofit conservative Christian advocacy group, said earlier this week the decision to withdraw “is inconsistent with what the president has done” to protect persecuted religious minorities.

Pat Robertson, founder of the Christian Broadcasting Network, warned that Trump “is in great danger of losing the mandate of heaven if he permits this [withdrawal] to happen.”

On Friday, Treasury Secretary Steven Mnuchin said the United States could “shut down the Turkish economy” if it targets ethnic and religious minorities in its military operations.