President Donald Trump responded to the Louvre Museum attack in Paris, France, reminding the country not to forget about terrorism.

“A new radical Islamic terrorist has just attacked in Louvre Museum in Paris,” he wrote on Twitter. “Tourists were locked down. France on edge again. GET SMART U.S.”

Trump’s decision to restrict immigration and refugees from several high-risk countries in the Middle East has created a firestorm of criticism from the left, causing major CEOs from companies like Uber and Walt Disney to distance themselves from the administration.

The Trump administration has defended the restrictions as a necessary step to protecting the country from radical terrorists, until more “extreme vetting” for people coming into the country can be put into place.

At the National Prayer Breakfast on Thursday, Trump explained why he wanted to spend more resources securing the nation’s borders.

“In the coming days, we will develop a system to help ensure that those admitted into our country fully embrace our values of religious and personal liberty and that they reject any form of oppression and discrimination,” he said. “We want people to come into our nation, but we want people to love us and to love our values, not to hate us and to hate our values.”