U.K. Prime Minister Theresa May has confirmed that no members of the British Royal Family or government ministers will attend the 2018 World Cup finals in Russia in the wake of the poisoning of former spy Sergei Skripal.

Skripal, 66, and his 33-year-old daughter, Yulia, remain in a critical condition after they were exposed to what U.K. authorities have described as a “nerve agent” in the English city of Salisbury earlier this month.

Last week, U.K. foreign secretary Boris Johnson said that “it will be very difficult to imagine that U.K. representation [at the World Cup] will go ahead in the normal way” if Russian involvement was proven. And on Monday, May said that Russian involvement in Skripal’s poisoning was “highly likely.”

Speaking in the House of Commons on Wednesday, May confirmed that no representatives would travel to Russia despite the England national team’s presence at the tournament.

Earlier this week, Russia’s foreign ministry said in a strongly worded statementthat any potential British World Cup boycott would damage both the relationship between the two countries and world sport.

May said on Wednesday that Russia has expressed “disdain” for Britain’s wish for an explanation into the attempted murder of Skripal and his daughter. She said that Russia’s actions “represent an unlawful use of force.”

May said that 23 Russian diplomats have a week to leave Britain — the single biggest such expulsion since the Cold War. She also announced a range of economic and diplomatic measures, including a decision to cancel all high-level bilateral contacts with Russia, as reported by Associated Press.

Russia has denied responsibility in the March 4 attack on the Skripals.