WASHINGTON - President Donald Trump accused OPEC of manipulating world oil markets and warned it to stop, while also saying the United States will sanction European companies that do business with Iran.Asked on Fox News' "Sunday Morning Futures with Maria Bartiromo" if someone was manipulating oil markets, Trump said, "OPEC is and they better stop it because we're protecting those countries, many of those countries. OPEC is manipulating."Trump also was asked on the news program that aired on Sunday if he will sanction European companies if they do business with Iran. He said, "Yep, of course. That's what we're doing, absolutely."