document: Theresa May used a speech in Washington to urge the UK's partners in the Five Eyes security alliance - the US, Canada, Australia and New Zealand - to work together against terrorism.
  Mrs May called for better information-sharing and more thorough exchange of terrorist finance details.
  She said tackling terrorism was the "challenge of our generation".
  Mrs May called on the UK's partners in the Five Eyes alliance to extend "the successful co-operation between our countries on issues of national security which we have built over past decades".
  "I am clear that defeating terrorism requires a global response, and that we will not succeed by acting in isolation," Mrs May said.
  She challenged the alliance to:
  "Extremism is spreading, threatening and taking lives, not just in our countries but in other lands. It thrives in the disorder created by fragile and failing states.
  "It is contributing to, and in some cases exploiting, mass migration. It is turning the benefits of modern technology to its twisted ends," she added.
  Fears have previously been raised that militants from the so-called Islamic State group may be attempting to get into Europe posing as refugees.
  Last month a report by EU's police agency Europol said there was no "concrete evidence" that militants were using the flow of refugees to enter unnoticed but it said there were reports that refugee centres were being "specifically targeted" by Islamic extremist recruiters.
summary: Extremism is contributing to and exploiting mass migration, the home secretary has warned.