British Defense Secretary Gavin Williamson | Jack Taylor/Getty Images Russia should ‘go away and shut up,’ says UK defense secretary Gavin Williamson uses first major speech to warn of Russian threat and announce new chemical weapons defense center.

Russia should “go away and shut up,” U.K. Defense Secretary Gavin Williamson said Thursday, describing worsening relations between the two countries.

The Salibsury attack, in which former Russian spy Sergei Skripal and his daughter Yulia were poisoned with a Russian-made nerve agent, is evidence Moscow is “ripping up the international rule book,” Williamson said.

"What is also clear is that the Kremlin is ripping up the international rule book, using its growing hybrid capabilities to subvert, undermine, and influence countries around the world,” he said, in his first major speech as defense secretary, in which he made a case for boosting U.K. defense spending.

“If we doubted the threat Russia poses to our citizens, we only have to look at the shocking example of their reckless attack in Salisbury,” he added.

Williamson also announced plans to build a new chemical weapons defense center as part of a larger plan to boost its efforts to tackle chemical warfare.

The £48-million center will be based at the U.K.'s Porton Down facility, which identified the nerve agent known as "Novichok" used in the Salisbury attack.

Williamson's statement follows U.K. Prime Minister Theresa May's decision Wednesday to expel 23 Russian diplomats in response to Russia's failure to explain how a nerve agent came to be used in the U.K. The Kremlin has denied any involvement in the incident.

"We have arrived at a profound moment in our history, a crossroads where the choice before us as a nation is simple — to sit back and let events overtake us or step forward," Williamson said.

As a precautionary measure, thousands of British soldiers will also be vaccinated against anthrax, in light of the growing chemical and biological threat from a range of state actors, Williamson said.