It was also revealed yesterday that a Russian nerve agent Novichok was used in the attack. "The attack was reckless, indiscriminate and irresponsible", White House press secretary Sarah Huckabee Sanders said. "We offer the fullest condemnation".
"Sanders said repeatedly that the United States stands with its ally, Britain, but it didn't join its conclusions about Russia's involvement yet", said Aaron Blake, of The Washington Post. Instead, Sanders said the administration is condemning the attack and "standing with our ally".
Investigators have concluded that it's "highly likely" Russia is responsible for poisoning the former Russian spy and his daughter found in Salisbury, England, last week, U.K. Prime Minister Theresa May said Monday.
May said she came to the conclusion based on an investigation of the chemical agent used in the attack in Salisbury and the knowledge that Russian Federation has produced this agent before.
The Trump administration has faced criticism for its muted criticisms of Russia and Russian President Vladimir Putin after the USA intelligence community determined Russia sought to interfere in the 2016 presidential election.
May gave Russian Federation until the end of Tuesday to respond to her allegations.
Russia, which has denied any role in the attack, said May's allegations were a politically motivated "circus act".