President Donald Trump says the United States must get tougher on illegal immigration.
Trump tweeted on Monday morning that sanctuary city policies are disgraceful.
He blamed Democrats and said the U.S. has been naive.
Trump also said Mexico "must stop people from going through Mexico and into the U.S."
He threatened to make it a "condition of the new NAFTA" agreement."
Trump also said Congress must move quickly to approve full funding for a massive border wall.