UK poisoning: Probe to 'leave no stone unturned'

British police will "leave no stone unturned" in hunting answers after two more people were exposed to the Novichok nerve agent on UK soil this week, Prime Minister Theresa May said Thursday.

"To see two more people exposed to the Novichok in the UK is obviously deeply disturbing, and the police I know will be leaving no stone unturned in their investigation," May said on a visit to Chancellor Angela Merkel in Berlin, adding her thanks for Germany's "unwavering support" following the March poisoning of former Russian spy Sergei Skripal.