Police in the United Kingdom announced on Wednesday that a former Russian Army officer who spied for the U.K. was attacked over the weekend with a nerve agent.
Sergei Skripal and his daughter Yulia are in critical condition after they were found unconscious on Sunday in Salisbury, a city in Southwest England, the Associated Press reports. After years of imprisonment in Russia, Skripal was granted refuge in the U.K. as part of a 2010 spy swap between the United States and Russia.
The two were previously known to have come into contact with an unknown substance when they were found, and an investigation is ongoing. A police officer who first responded to Skripal and his daughter is also being treated in the hospital.
Metropolitan Police counterterrorism chief Mark Rowley made the confirmation that the pair had come into contact with a nerve agent and that they were believed to have been "targeted specifically."
"Having established that a nerve agent is the cause of the symptoms leading us to treat this as attempted murder, I can also confirm that we believe that the two people who became unwell were targeted specifically," Rowley said.
Russia has denied responsibility for the attack, despite the similarity between this attack and the death of ex-spy Alexander Litvinenko, who was killed by radioactive poisoning in London back in 2006. An investigation into Litvinenko's death concluded Russian agents poisoned him by lacing his tea with radioactive polonium-210 and that the killing was likely approved by Russian President Vladimir Putin. Russia has also continued to deny involvement in Litvinenko's death.
Britain has said it will respond strongly if the Russian government is linked to the latest attack.
A banned nerve agent was used in the assassination of North Korean dictator Kim Jong Un's half-brother in Malaysia last year.