An NHS emergency ambulance is pictured outside the door of 10 Downing Street, the official residence of Britain's Prime Minister, in central London on May 15, 2017. A cyber strike which hit dozens of British hospitals on Friday is part of a wider "international attack", Prime Minister Theresa May said. The state-run NHS declared a "major incident" after the cyber attacks, which prompted some hospitals to divert ambulances and scrap operations. / AFP PHOTO / Daniel LEAL-OLIVAS