US President Barack Obama says systemic failures among intelligence agencies to detect a Christmas Day plane plot are his responsibility, maintaining "the buck stops with me". As he unveiled a series of security reforms, Obama again criticised intelligence services for failing to connect the dots and forewarn US officials earlier that an attack was being planned. "All of these agencies and their leaders are responsible for implementing these reforms. And all will be held accountable if they don't," Obama said in a brief White House statement on Thursday. But the president added: "I am less interested in passing out blame...