Britain is accusing Russia of manufacturing and stockpiling a deadly nerve agent in violation of international law. Foreign Secretary Boris Johnson says he has evidence that Russia has been creating and storing the toxin, which was recently used to poison a former spy in England.
In an interview on the BBC's Andrew Marr Show, Johnson said, "We actually have evidence within the last 10 years that Russia has not only been investigating the delivery of nerve agents for the purposes of assassination, but has also been creating and stockpiling Novichok."
Novichok is a military-grade nerve agent, and was identified as the weapon used to poison former spy Sergei V. Skripal and his daughter, Yulia Skripal, in the city of Salisbury, in southwestern England, on March 4.
According to The New York Times, exposure to Novichok, "either by inhalation or through the skin, leads to muscle spasms, secretion of fluid into the lungs and organ failure, sometimes accompanied by foaming at the mouth. But if the victim has already died, experts said, the police could easily mistake the cause of death for a simple heart attack."
Russian officials have suggested that Britain was responsible for the poisoning of the Skripals, and had samples of the nerve agent at its chemical weapons facility, Porton Down, which is about 8 miles from Salisbury. The Times also reported Russian senior diplomat Alexander Shulgin said on Saturday that Russia had discontinued its chemical weapons production when the Soviet Union collapsed.
Johnson described Russia's response to the BBC, saying, "It has been a sort of mixture of smug sarcasm and denial, obfuscation and delay." On Russia's Porton Down suggestion, Johnson said, "It was not the the response of a country that really believes it's innocent, that really wants to engage in getting to the bottom of this matter."
In retaliation for Skripal's poisoning, Britain said it would expel 23 Russian intelligence officers working in the embassy in London. On Saturday President Vladimir V. Putin of Russia responded that it would expel 23 British agents from the country, and shut down a British cultural center in Moscow.
The tit-for-tat may continue this week. Britain's national security council will meet to consider further measures, and The Guardian reports that Johnson has pledged to use existing sanctions to "crackdown on unexplained wealth that may have been obtained by corruption, or where there was evidence of a link with the Kremlin and Vladimir Putin."
Russia's ambassador in London told The Daily Mail, the "dispute is indeed escalating dangerously and out of proportion."
On Monday analysts from the U.N.-backed Organization for the Prohibition of Chemical Weapons will arrive in Britain to test samples of the nerve agent used in the poisoning.