A policeman who attended the crime scene of a former Russian agent poisoned by a nerve agent is now talking with police officers after his condition improved. The former Russian double agent and his daughter were left critically ill in British hospital after they were targeted by a nerve agent in an attempt to kill them, British police confirmed Wednesday. Declining to name the nerve agent used, UK Home Secretary Amber Rudd described it as a "very rare" substance, though insisted there was little risk to the wider public. Though the policeman's condition has improved, authorities warned it remained "serious", the two Russians, Sergei Skripal, 66, and his 33-year-old daughter Yulia Skripal, remain in a coma. Last night, another former Russian agent exiled in the UK, Valery Morozov, claimed that Mr Skripal had maintained ties with Russian intelligence and visited the Russian embassy in London "every month". Mr Morozov told Channel 4 news “If you have a military intelligence officer working in the Russian diplomatic service, living after retirement in the UK, working in cyber-security and every month going to the embassy to meet military intelligence officers – for me being political refugee, it is either a certain danger or, frankly speaking, I thought that this contact might not be very good for me because it can bring some questions from British officials." The Russian embassy in London denied any contact between Mr Skripal and its staff. The attack was "being treated as a major incident involving attempted murder by administration of a nerve agent,” said Assistant Commissioner Mark Rowley, the UK’s most senior counter-terrorism official. “I can also confirm we believe the two people were targeted specifically," he said. "Our role now is of course to establish who is behind this and why they carried out this attack.” The comments by Mr Rowley were the first time that British authorities had confirmed that the incident on Sunday in the southern British city of Salisbury was an attempted killing. Scientific tests by government experts have identified the specific agent used which could help trace those responsible for the attack, police said in a statement. Police have declined to identify the specific agent. Mr Rowley did not mention Russia in brief comments to the media but the use of nerve agent has increased the likelihood that it was a state-sponsored attack. Nerve agent can be administered in liquid and spray form and attacks the nervous system. It is ingested through food and drink, the skin and by breathing it in. It can lead to paralysis and respiratory failure. _______________ <strong>Read more:</strong> _______________ The most deadly nerve agent VX was used in the murder of Kim Jong-nam, the estranged brother of North Korea’s leader, at Kuala Lumpur international airport in February last year. He died within 20 minutes of two women smearing his face with cloths impregnated with the deadly agent. The two women are currently on trial for the attack in Malaysia but prosecutors believe the attacks was sponsored by the North Korean state. Another nerve agent, sarin, was used in an attack by Syrian government forces on Ghouta, on the outskirts of Damascus, in 2013 which killed some 1,400 people. Saddam Hussein also used nerve agent against his own people in the Kurdish town of Halabja in 1988. Home Secretary Amber Rudd confirmed that police had an update about the substance after being briefed by senior counter terrorist officers at an emergency response meeting on Wednesday. “We need to keep a cool head and collect all the evidence we can,” said Ms Rudd. “We need to make sure that we respond not to rumour but to all the evidence they collect and then we will have to decide what action to take." Mr Skripal was once a colonel in Russia's GRU military intelligence service but was convicted in Russia in 2006 for betraying dozens of Russian agents to British intelligence in exchange for financial reward. He was given refuge in 2010 in Britain as part of a <a href="https://www.thenational.ae/world/the-americas/russia-us-spy-swap-defuses-tensions-1.538855">spy swap between the US and Russia.</a> At the time of his release, the Russian president Vladimir Putin said in a television interview that "traitors will kick the bucket". He went on: "Whatever they got in exchange for it, those 30 pieces of silver they were given, they will choke on them." Professor Anthony Glees, a security expert at the University of Buckingham, said if Russia was found to be behind the attack it would be an "act of extreme recklessness". It would signal the "beginning of a new Cold War between Britain and Russia," he told Sky News. The pair were found unconscious on a bench on Sunday afternoon outside a shopping centre in Salisbury. Yulia Skripal, who lives in Moscow, was believed to be visiting her father in the UK. A nearby Zizzi pizza restaurant and a pub called The Bishop’s Mill in Salisbury remained closed off, while parts of parts of Solstice Park, including an ambulance station, were also cordoned off by police. Police appealed for witnesses or anyone with any information to come forward and to send footage of pictures of the area that they may have taken around the time. Mr Rowley said: "We would like to hear from anybody who visited the area close to the Maltings shopping centre where these two people were taken ill on Sunday afternoon, and may have seen something that could assist the investigation.” Britain’s foreign secretary warned of reprisals on Tuesday afternoon if the Kremlin was found to have had any involvement in the suspected poisoning. Mr Johnson told lawmakers that Russia was a “malign and disruptive” force but stopped short of directly blaming Moscow for Mr Skripal’s condition. “I’m not now pointing fingers,” he said. “But I say to governments around the world that any attempt to take innocent life on UK soil will go neither unsanctioned nor unpunished.” More details have emerged about Mr Skripal and his family since news broke of the suspected attack on Monday. Family members told the BBC that Mr Skripal’s wife, elder brother and son had died in recent years, some in suspicious circumstances. Alexander Skripal, Mr Skripal’s son, died mysteriously last year in St Petersburg from liver failure, relatives told the broadcaster. It is believed Ms Skripal, who works for Pepsico in Moscow, was visiting the UK, where her late brother is buried, to coincide with what would have been his 44th birthday. Mr Skripal’s wife Liudmila Skripal, who died in 2012 from cancer, is also buried in Salisbury. The case has drawn comparisons to the Kremlin-backed murder of former agent Alexander Litvinenko, who was killed in 2006 after lethal radioactive polonium 210 was slipped into his tea during a meeting with two Russian agents in London. Russia has said it is open to working with British police on the investigation if requested but denied the Kremlin had anything to do with the incident. The Russian embassy in London said in a statement: "Media reports create an impression of a planned operation by the Russian special services, which is completely untrue."