LONDON — Russia's covert operations against its former agents were thrown back in the spotlight with new developments Tuesday in a pair of high-profile incidents that took place on British soil.

Police identified a third suspect in the attempted poisoning of a former Russian double agent in 2018, and the European Court of Human Rights said Russia was responsible for the 2006 killing in Britain of former KGB agent Alexander Litvinenko.

For the first time, police described all three men allegedly involved in the 2018 attempt against Sergei Skripal and his daughter in England as Russian military intelligence operatives.

Speaking in Parliament on Tuesday, British Home Secretary Priti Patel called the nerve agent attack “utterly, utterly reckless” and not the first time that Russia has carried out a “brazen attack” on British soil.

Patel said the British government would “continue to respond extremely robustly to the enduring and significant threat from the Russian state.”

“We respect the people of Russia, but we will do whatever it takes, everything it will take to keep our country safe,” she said.

The newly identified Denis Sergeev, who used the alias Sergey Fedotov when traveling in Britain, was charged with conspiracy to murder, attempted murder, grievous bodily harm, possession and use of a chemical weapon.

It was a spy poisoning drama that rocked a nation. In March 2018, police found Skripal and Yulia, his adult daughter, slumped on a park bench in Salisbury, in southern England.

It was later discovered that the pair had been poisoned with Novichok, a rare nerve agent developed by the Soviet Union. One of the police officers who touched Skripal’s front-door handle, which was smeared with the nerve agent, was later hospitalized.

They all survived, but another British woman died after she sprayed herself with Novichok contained in a discarded perfume bottle allegedly used in the attack.

The case inflamed diplomatic tensions between Moscow and the West. Theresa May, who was Britain’s prime minister at the time, pointed the finger at Russia. Hundreds of diplomats were expelled by Russia and Western nations.

British police have already charged two other suspects in the case — Alexander Mishkin, who used the alias Alexander Petrov while in Britain, and Anatoliy Chepiga, who went by Ruslan Boshirov.

Russia has vehemently denied any involvement. Officials even put the pair on Russian television, where they claimed they were just sightseeing tourists who happened to be in a famed cathedral town around the same time as the attack.

While this was the first time Sergeev had been named by British authorities, he had previously been identified by the Bellingcat journalism website after a months-long investigation. Sergeev was alleged to have been part of a unit that was involved in the poisoning of an arms dealer in Bulgaria in 2015.

Russia said there was no factual basis to the British accusations that Sergeev was involved in the poisoning and called the charges politically motivated.

“The leadership of the United Kingdom continues to use the Skripals as a tool to pressure our country and to stir up anti-Russian sentiment in British society,” Russian Foreign Ministry spokeswoman Maria Zakharova said at a news conference. 

Dean Haydon, senior national coordinator for British counterterrorism policing, said the trio had “previously worked with each other and on behalf of the Russian state as part of operations carried out outside of Russia.”

“We can’t go into the detail of how, but we have the evidence that links them to the GRU,” Haydon added, a reference to Russia’s military intelligence agency.

He described the three suspects as “dangerous individuals” who “tried to murder people here in the U.K. and also brought an extremely dangerous chemical weapon into the U.K. by means unknown.”

Police released a grainy photo of Sergeev arriving at Heathrow Airport on March 2, 2018, and said that before he left Britain on March 4, he met his colleagues several times in London.

Police said they would apply for an Interpol notice to be issued for Sergeev on Tuesday. Britain does not have an extradition agreement with Russia, but if any of the three suspects were to visit a country outside of Russia that has such an agreement, they could be extradited to Britain and brought to trial.

Meanwhile, the European Court of Human Rights said Tuesday that Russia was responsible for the killing of Litvinenko, a former KGB agent who died in London in 2006 after drinking tea spiked with a radioactive material.

The findings echo those in 2016, when a British inquiry concluded that the killing of Litvinenko, an outspoken critic of the Kremlin who had defected to Britain, was “probably approved” by President Vladimir Putin.

Kremlin spokesman Dmitry Peskov said the ECHR’s judgment was unsubstantiated because the court could not have all available facts. “It is unlikely that the ECHR holds any authority or technical capacity to possess information on this score,” he said. “You know that this investigation hasn’t produced any results thus far. Therefore, making such claims is groundless, to say the least.”

Andrei Lugovoi, a parliamentary deputy implicated by Britain in the Litvinenko murder, said he considered the ECHR decision “unjust, illegal, politically biased.” Britain’s director of public prosecutions said in 2007 that there was enough evidence to charge Lugovoi in the killing.

Lugovoi also dismissed the ECHR finding that Russia did not properly investigate the matter. “This is not true. The Russian prosecutor’s office and the Investigative Committee did everything to establish the truth,” he told the Interfax news agency.

Dixon reported from Moscow.