UK Prime Minister Theresa May announced a range of economic and diplomatic measures, including the suspension of high-level bilateral contacts with Russia. An invitation for Russian Foreign Minister Sergey Lavrov to visit Britain has been canceled, and May said British ministers and royals will not attend the soccer World Cup in Russia this summer, Daily Sabah reported.

May also said Britain would clamp down on murky Russian money and strengthen its powers to impose sanctions on abusers of human rights.

"We will freeze Russian state assets wherever we have the evidence that they may be used to threaten the life or property of U.K. nationals or residents," May said, without giving details.

May announced the measures after Moscow ignored a midnight deadline to explain how a nerve agent developed by the Soviet Union was used against Sergei and Yulia Skripal. The father and daughter remain in critical condition in a hospital in Salisbury, southwestern England.