ISIS claims responsibility for London attack

LONDON -- The Islamic State of Iraq and Syria (ISIS) on Sunday issued a claim of responsibility for an attack that killed seven people in a busy area of Central London.In a statement more than 24 hours after the attack, the group's Aamaq news agency quoted a "security source," saying, "A Unit of Islamic State Fighters carried out London attacks yesterday."Prime Minister Theresa May on Sunday called for tougher measures to contain Islamic extremism in Britain.May, facing an election Thursday, sai