President Trump has doubled down on his claims that migrant caravans heading for the U.S. border represent an “invasion” and further stoked fears of “dangerous” people within their ranks, saying Wednesday that the caravans are “larger than reported” and full of “rough people.” Speaking to ABC News, Trump said his decision to send up to 15,000 troops to the U.S. border to deal with the caravans is justified because “you have caravans coming up that look a lot larger than it’s reported actually.” Without citing any official figures, Trump said the caravans are likely “a lot bigger than people think.” “I’m pretty good at estimating crowd size,” he said. Border authorities have previously said two caravans with about 6,500 migrants are heading for the U.S., though about 2,000 members of the caravans have reportedly accepted an offer to remain in Mexico. Trump suggested Wednesday that military troops sent to the border could arrest the migrants because “they can’t invade our country.” “When you look at some of the people within the caravan, yeah, I think it could be considered an invasion of our country. … they are some dangerous people. These are some rough people,” he told ABC News.