LONDON (Reuters) - British Prime Minister Theresa May called on Tuesday for a “long-term response” by the West to the security threat from Russia as NATO followed member states in expelling Russian diplomats over the poisoning of a double agent in England. Mattis said the Salisbury incident involved the "pretty obvious" use of a "weapon of mass destruction," which the British government has identified as the military-grade nerve agent Novichok, developed by Russia during the Cold War.
Former Ukrainian President Viktor Yushchenko, himself the victim of a September 2004 poisoning, calls for military action to be considered against Russia.