On Monday, the United States announced that it would be joining the growing list of vexed nations expelling Russian diplomats and officials from their borders, following the use of a Soviet-era nerve agent on a former Russian spy on British soil.

With 60 Russians being ordered out of the United States and at least 40 more from 18 European nations and Canada, the exodus of Kremlin officials headed back to Moscow is perhaps not unprecedented, but historic nonetheless, and on Tuesday, American Secretary of Defense James Mattis did not mince words regarding his stance on the topic.

On March 4th, a Soviet produced nerve agent known as Novichok is believed to have been used in the attempted assassination of former Russian Military Intelligence officer turned MI6 informant, Sergei Skripal. Exposure to the weapon left both Skripal and his 33 year old daughter in critical condition, along with the first responding officer in the shopping square of Salisbury, England. At least 30 others ultimately had to seek treatment following exposure to the substance that the international community has claimed came from Soviet labs. Russia, however, has countered with a number of contradicting claims, all placing the blame for the incident on someone else.

According to Mattis, there’s little question as to who was responsible for the attack. When it came up during a press briefing on Tuesday he referred to the incident as, “the Russian … apparent, pretty obvious, Russian use of a weapon of mass destruction, a chemical agent, for the first time in Europe since World War II.”

When asked to clarify what he thought had happened in England, Mattis replied, “Attempted murder of a man and his daughter, how’s that for starters?”

Mattis, who has pulled no punches in the past when characterizing Russia as a threat to the United States, lamented Russia’s role as a constant antagonist on the global stage. He recounted a time when it seemed as though relations between Russia and the United States might even improve.

I think a number of us with my color hair can remember Russian marines in North Carolina working with U.S. Marines as we prepared for possible deployments together on U.N. peacekeeping missions — humanitarian relief,” Mattis said. “That, regrettably, by Russia’s choice, is now a thing of the past.”

US expels 60 Russian officials in wake of UK nerve agent attack

Read Next: US expels 60 Russian officials in wake of UK nerve agent attack

He went on to call the use of the nerve agent in Salisbury, England “reckless,” using it as an example of Russia’s choice to “seek a different relationship with the NATO nations,” as opposed to a mutually beneficial one.

According to the Defense Secretary, the assassination attempt in Salisbury was just one example of a broader foreign effort.

They take insignia off soldiers’ uniforms and they go into Crimea.  They say they have nothing to do with what’s going on with the separatists in eastern Ukraine; I’m not sure how they can say that with a straight face.  They point out that it can’t be proven who had tried to kill the person in Salisbury.” He listed. “They’re doing things they believe are deniable.”

Feature Image Courtesy of the Department of Defense