WASHINGTON - US President Donald Trump on Friday denounced an attack in London when a blast hit a packed commuter train, and urged authorities and others to take more "proactive" steps such as better policing of internet use by terrorist groups."Another attack in London by a loser terrorist. These are sick and demented people who were in the sights of Scotland Yard. Must be proactive!" Trump wrote in a post on Twitter."Loser terrorists must be dealt with in a much tougher manner. The internet is their main recruitment tool which we must cut off & use better!"