Which issue has developed into the most serious diplomatic crises between Russia and the West since Moscow's seizure of Crimea?
Q1. Which issue has developed into the most serious diplomatic crises between Russia and the West since Moscow's seizure of Crimea?
Answer: Poisoning former Russian Spy in UK
Explanation: The poisoning of former Russian spy Sergei Skripal and his daughter in Salisbury, UK in March 2018 triggered the most serious Russia-West diplomatic crisis since Russia's annexation of Crimea.