WASHINGTON (Reuters) - U.S. President Donald Trump said on Friday he was preparing to call British Prime Minister Theresa May after a home-made bomb on a London train injured 22 people. Trump, who spoke briefly with reporters before going into the Oval Office, said he had been briefed on the attack, which police called a terror incident, calling it a  terrible thing.  Asked about a Friday morning tweet in which Trump said the U.S. ban on travelers from certain countries should be more  specific,  Trump said:  We have to be tougher and we have to be smarter.  (This story corrects third paragraph to show Trump was referring to the U.S. travel ban in his quote, not the London attack.)  
Trump says to call UK's May on Friday following train blast