Russian Federation has dismissed the accusations as "fairy tales" and denied any involvement in the attack which landed the Skripals, along with a British police officer, in the hospital.
"It's striking the contrast between what the Brits have done and what the USA has not done", said Angela Stent, director of Georgetown University's Center for Eurasian, Russian, and East European Studies. Britain has not offered proof of their allegations against Russian Federation, but Haley seemed contented to endorse it publicly.
But he was quoted by others as saying that Russian Federation would inform British authorities first before any media announcement.
Interfax quoted the foreign minister as saying a motive behind the UK's actions might be to complicate Russia's hosting of Fifa's World Cup this summer.
Putin will make the final decision on the sanctions being worked out by his Foreign Ministry, which has been predicted to be the expulsion of "dozens" of British diplomats and intelligence operatives.
What is the latest from the UK?
Foreign Secretary Boris Johnson stepped up the war of words with Russian Federation on Thursday.
Mr Johnson said: "Now is the moment for Putin to jam the lid down and send a signal to people: "You do this, you're going to die".
Presenting Britain's case, Deputy UK Ambassador to the UN Jonathan Allen called the attack "an unlawful use of force" and invited representatives from the Organization for the Prohibition of Chemical Weapons to conduct an independent investigation of the incident.
But he added that Russia's "smug, sarcastic" response indicated their "fundamental guilt".
The Russian foreign minister on Thursday said Moscow would respond by expelling British diplomats "soon".
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Chelsea striker Olivier Giroud believes his team deserved more. "He's writing with his team-mates a great story with Barcelona ". Often seen as a pro Real Madrid newspaper, Marca also acknowledged the Argentine's brilliance.
Defence Secretary Gavin Williamson said Russian Federation "should go away and should shut up". And quite frankly, after a year, we didn't get very far.
Skripal, 66, and his 33-year-old daughter, Yulia, remain in critical condition after being found unconscious March 4 in Salisbury.
The source of the nerve agent used - which Britain says is Soviet-made Novichok - is unclear.
In an online post, the Russian committee said the attempt on Yulia Skripal's life was "committed in a risky manner endangering other people, in Salisbury".
The global chemical weapons watchdog says the class of nerve agents used in the Skripal attack has never been declared by any of its member states.
Mr Lavrov also said the UK's approach to the matter was partly prompted by the government's problems over Brexit.
But after Tuesday's deadline passed, the United Kingdom announced the expulsions. Government officials and members of the Royal Family will also not be attending the soccer World Cup to be held in Russian Federation later this summer.
How have other nations reacted?
On Thursday evening French President Emmanuel Macron refused to visit the Russian stand at the Paris Book Fair.
He said: "I condemn in the strongest possible terms this unacceptable attack". Trump should have learned from their errors, but at least he's starting to learn now that the problem with Russian Federation wasn't a deficit of friendliness from the US.
On Wednesday, the White House said it "stands in solidarity" with "its closest ally" the United Kingdom and supported its decision to expel the Russian diplomats.