Watch U.S. Presidential Candidates React to Brussels Attacks

U.S. presidential hopefuls on Tuesday condemned the terrorist attacks in Brussels but differed in their approach to fighting ISIS.

Both Republican and Democratic candidates issued statements after the coordinated attacks in the Belgian capital that left 31 people dead and more than 100 others wounded.

Hillary Clinton called the “sophisticated” bombings “deeply distressing,” while urging Americans to stand in solidarity with Europeans. “We have to intensify our efforts to find and prevent terrorists from ever doing this again,” she said during an appearance on NBC’s Today show. “It’s going to be a long challenge because of many factors including the easy accessibility to powerful explosives and the mobility of terrorists but we’ve got to be absolutely strong and smart and steady in how we respond.”

Republican frontrunner Donald Trump said the U.S. “must be vigilant and smart” in one of many tweets after the tragedy. “Do you all remember how beautiful and safe a place Brussels was,” he wrote. “Not anymore, it is from a different world!”

“This madness must be stopped, and I will stop it,” he said in another tweet.

Watch the other candidates’ reactions above.