Putin urges the men to address the media saying there was 'nothing criminal' about them, as he speaks at an economic forum in the far eastern city of Vladivostok
The Daily Telegraph newspaper, citing an unnamed security source, says the two men had posed as businessmen to obtain their visas from the British consulate in Saint Petersburg.
The action by the US State Department is the latest salvo in a series of disputes between the rival powers, and comes less than a month after US President Donald Trump met his Russian counterpart Vladimir Putin in Helsinki
The State Department says the action is aimed at punishing President Vladimir Putin's government for having 'used chemical or biological weapons in violation of international law'
(UPDATED) Kremlin spokesman Dmitry Peskov tells reporters the case is 'very worrying' but Russia had no information 'about what substances were used and how they were used'
The two patients 'are both currently receiving treatment for suspected exposure to an unknown substance at Salisbury District Hospital,' Wiltshire police says
NATO has vehemently criticized Moscow over the attack in March and has expelled 7 Russian diplomats as part of a coordinated international response
The accusations come as diplomats from the Organisation for the Prohibition of Chemical Weapons meet behind closed-doors in The Hague to discuss the crisis
'We call on Russia to urgently address all questions related to the incident in Salisbury,' foreign ministers of the Group of Seven industrialized nations say in a joint statement
The Russian ambassador in London has sent a 'personal note' to British Foreign Secretary Boris Johnson asking for the meeting
Russia responds to the new US sanctions against their most influential oligarchs
'I woke up over a week ago now and am glad to say my strength is growing daily,' says Yulia Skripal
(UPDATED) The Russian government tells citizens to think twice about going to Britain, saying they could be singled out for harassment there
In total, 171 people will leave the country, state news agency TASS reports Russian ambassador to the US, Anatoly Antonov, as saying
(UPDATED) Meanwhile, Britain says it is considering Moscow's request for consular access to Yulia Skripal, daughter of poisoned former double agent Sergei Skripal
London has shared 'unprecedented levels of intelligence with partners' since the attack, a senior government official says, culminating in the response from capitals around the world
A number of member states are considering following Britain's lead and expelling Russian intelligence agents posing as diplomats, with German Chancellor Angela Merkel saying further coordinated actions were "necessary"
'I would like to express my sincere gratitude to you for your bravery when reacting to the assault on two Russian nationals,' says the Russian ambassador as he insists on Moscow's innocence
Foreign Secretary Boris Johnson says the Kremlin targeted the country due to London's criticism of Russian rights abuses
'Sooner or later these unsubstantiated allegations will have to be answered for: either backed up with the appropriate evidence or apologized for,' says Vladimir Putin's spokesperson Dmitry Peskov
Moscow expels 23 British diplomats following London's 'provocative' measures over poisoning of ex-double agent Sergei Skripal and his daughter
(UPDATED) The crisis erupts after Sergei Skripal and his daughter Yulia were exposed to a Soviet-designed nerve agent, leaving them in critical condition
Aside from probing the 'attempted premeditated murder of Yulia Skripal, Russia's Investigative Committee will also probe the the suspected murder of a Russian living in London, Nikolai Glushkov
'We share the UK assessment that there is no plausible alternative explanation, and note that Russia's failure to address the legitimate request by the UK government further underlines its responsibility,' a joint statement by the UK, France, Germany, and the USA reads
British Prime Minister Theresa May says Russia failed to respond to her demand for an explanation on how a Soviet-designed chemical, Novichok, was used in the English city of Salisbury
Britain will brief council members during the open meeting at 1900 GMT on the nerve agent that left ex-spy Sergei Skripal and his daughter in critical condition, the British mission to the United Nations says
Foreign Minister Sergei Lavrov insists 'Russia is not guilty,' saying it is ready to cooperate with Britain but complaining that its request for samples of the nerve agent has been rejected
'It is extremely worrying that chemical agents are still being used to harm people. Those found responsible for this use must be held accountable for their actions,' Ahmet Uzumcu director-general of the Organization for the Prohibition of Chemical Weapons, says.
In a dramatic escalation of diplomatic tensions over the incident, Prime Minister Theresa May says in parliament that the nerve agent used to poison the pair was a military-grade type developed by Russia
The March 4 attack on former double agent Sergei Skripal and his daughter Yulia is being treated by detectives as attempted murder
On Wednesday, March 7, British police confirm for the first time that a nerve agent was used and that their probe was now an attempted murder investigation