Assistant Commissioner Neil Basu, National Lead for Counter Terrorism Policing revealed this after British authorities named two men, Alexander Petrov and Ruslan Boshirov, believed to be from Russia's military intelligence service, the GRU, as the main suspects in the March 4 attack in the southern English city of Salisbury.
Moscow has denied involvement in the poisonings since the beginning of the case and the issue reared up again on Wednesday when Britain said it had identified two alleged agents of Russia's GRU military intelligence service as suspects.
"We have full confidence in the British assessment that the two suspects were officers from the Russian military intelligence service, also known as the GRU, and that this operation was nearly certainly approved at a senior government level", the statement issued by Canada, France, Germany, and the United States says.
Also again indicated that the operation of the GRU in the assassination of Sergei Skripal "was nearly certainly approved at the highest level of the Russian state".
Prime Minister Theresa May told lawmakers that British intelligence has concluded that the two men are officers of Russia's GRU military intelligence service.
She is expected to speak to other leaders over the next few days as she seeks to forge an worldwide alliance for further action against Russian Federation.
Russian Foreign Ministry spokeswoman Maria Zakharova told the media, Wednesday, that the names of the two men mean nothing to them, and urged the British government to work with them, instead of resorting to "information manipulations".
British prosecutors accuse Petrov and Boshirov of conspiracy to murder Skripal, attempted murder and the use of a banned chemical weapon.
"This is a message to the Russian intelligence community and spy community that you do not sell out Putin to the West or there are going to be serious consequences", he said.
Russian defense and security analyst Pavel Felgenhauer said authorisation to attack the Skripals had also likely come "from the very top". As a result, Basu said, police weren't yet ready to lay charges in the second poisoning, though the two Russians are the prime suspects.
Hours later, the men left the United Kingdom on a flight from Heathrow to Moscow - two days after they had arrived at Gatwick.
Quake halts all trains on Japan island
Government spokesman Yoshihide Suga said two people had been killed, with local media reported around 40 were missing. Houses in the town were hit by landslides, and one report said five residents were found with no vital signs.
After the attack, allies in Europe and the United States sided with Britain's view of the attack and ordered the biggest expulsion of Russian diplomats since the height of the Cold War.
The Skripals survived the poisoning but a local man, Charlie Rowley, picked up a fake perfume bottle containing Novichok weeks later.
While traces of Novichok were found in the London hotel room the suspects used, there is no risk to other guests who were staying at the hotel at the time, the Met Police said.
Moscow has maintained it was not involved, with Russian Ambassador to the UN Vassily Nebenzia saying on Thursday the latest allegations by London and its allies were designed "to unleash a disgusting anti-Russian hysteria".
Police released security camera images of the two suspects and outlined a three-day mission that took them from Moscow to London to Salisbury, where they sprayed poison on Skripal's door before flying back to Moscow hours later. Britain charged two Russians with his murder but both remain in Russia, and one later won a seat in parliament.
Britain plans to press its case against Russian Federation at the U.N. Security Council later on Thursday.
Viktoria Skripal also said that she doubts that Sergei Skripal is still alive because he has not communicated with the family since the poisoning.
Ms Sturgess, who died after being exposed to novichok, and Mr Rowley, were not targeted intentionally, May said, but rather were victims of "the reckless disposal of this agent".
Basu said they were around 40 years old.
Basu would not comment on whether the Skripals had faced threats before the attack or where they were now located.
I know how much frustration there can be when you can't do the thing that you want to do. "I was a kid then; now i am much older". He will take a 14-4 winning record against Del Potro into Sunday's final having won six out of their last seven meetings.
Kei Nishikori is headed to the US Open semifinal following a dramatic upset victory over Marin Cilic on Wednesday. Keys said she will look to home support on Thursday when she resumes her rivalry with Osaka.
Meanwhile there has been further debate over Williams' charge that she had been a victim of sexism from the chair. In her post-match news conference Williams said she did not understand why Mouratoglou would say he was coaching.
The rise of groups like ISIS in Afghanistan can partly be attributed to the radical ideology he so aggressively propounded. After the fall of the Taliban regime in the 2001 US-led invasion, he had joined the insurgency.
We're thinking of Mac's loved ones at this tragic time. "I want to be able to have good days and bad days", he said. Sometimes, guilt can keep relationships together far longer than actually being in love can.
Maximum sustained winds of the unnamed system have been clocked at 30mph and the system is moving west-northwest at 15mph. If Gordon were to take more of a turn to the north then our forecast could change considerably by Wednesday and Thursday.
He said he had heard reports that Damascus had set a September 10 deadline for diplomacy to work before attacking. Iranian Foreign Minister Mohammad Javad Zarif said on Monday that terrorists should be "cleaned out" of Idlib .
Elon Musk hits massive blunt in live interview
Musk announced later in August that the company would remain public . "I'm not a regular smoker of weed", Musk said. The day after he started, Musk tweeted he was considering taking the company private with "funding secured".
Elon Musk smokes marijuana live on web show
It later said that Chief People Officer Gaby Toledano would not return from a leave of absence, just over a year after joining. Tesla's stock dropped 6 percent in Friday's pre-market session, trading around $263.55 at time of publication.
Mac Miller Dead At 26 From Apparent Overdose
TMZ reports that Miller was found dead in his home in California earlier today from what's been described as an apparent overdose. He was found to have a blood alcohol content twice the legal limit after the incident, and was charged with DUI as a result.
Blood-testing company Theranos is set to dissolve
Holmes stepped down from her position as CEO, and as Tuesday's announcement made clear, the company she founded will be no more . As part of the settlement, Ms Holmes had to return millions of shares to the privately held company and pay a $500,000 fine.
Champion Stephens booted from US Open
Sevastova broke the 25-year-old American's serve twice in the opening set, then broke her again to take a 2-0 lead in the second. Next up for the 28-year-old is Serena , who beat Pliskova later in the day to move into the semis.