WHITE HOUSE - The White House is stopping short of blaming Russia for the poisoning of a former Russian military intelligence officer who was a double agent for Britain's intelligence services.
"The use of a highly lethal nerve agent against U.K. citizens on U.K. soil is an outrage," White House Press Secretary Sarah Huckabee Sanders told reporters Monday. "The attack was reckless, indiscriminate and irresponsible. We offer the fullest condemnation and we extend our sympathy to the victims and their families and our support to the U.K. government."
WATCH: Spy investigation
?Sanders added that the United States stands by "our closest ally and the special relationship that we have," but she did not share in London's strong accusations toward Moscow for the March 4 poisoning of Sergei Skripal and his daughter, Yulia, in Salisbury. Both remain hospitalized in critical condition.
"I think they're still working through even some of the details of that," replied Sanders to a reporter's question about whether Russia is to blame.
"It actually sounds like a measured response and that's fine and it should be," the Stimson Center's director of nuclear safeguard, Cindy Vestergaard, tells VOA. She explains that U.S. authorities will likely prefer to review evidence compiled by the British before pointing a finger at Moscow.
"As with any state declaring chemical weapons perpetrators, others need to confirm the facts before doing the same," said Vestergaard, who has studied chemical assassinations. "Even then, the preference is still for the Organization for the Prohibition of Chemical Weapons — an international organization tasked with verifying and implementing the Chemical Weapons Convention — to do the same."
U.K. Prime Minister Theresa May told Parliament earlier in the day that it is "highly likely" Russia is responsible for the attack with the military-grade Novichok nerve agent, and that Moscow has until Wednesday to respond.
"Should there be no credible response, we will conclude that this action amounts to an unlawful use of force by the Russian state against the United Kingdom, and I will come back to this House and set out the full range of measures we will take in response," the prime minister warned.
"This is a circus show in the British Parliament," Russian Foreign Ministry spokesperson Maria Zakharova told reporters.
Criticism for Trump
"This reckless, targeted hit-job was an attack against the United Kingdom and we must condemn it," Congressman Adam Kinzinger, a Republican from the state of Illinois, said on Twitter.
NATO Secretary General Jens Stoltenberg said the use of any nerve agent "is horrendous and completely unacceptable."
"The U.K. is a highly valued ally, and this incident is of great concern to NATO. NATO is in touch with the U.K. authorities on this issue," Stoltenberg said.
President Donald Trump has faced criticism for his lack of tough words about Russia and its president, Vladimir Putin, after U.S. intelligence agencies determined that Moscow sought to interfere in the 2016 presidential election.
On Monday, 140 members of the opposition Democratic Party called on Trump to impose sanctions on Russia.
The Democrats say Trump is "ignoring the law" by not imposing sanctions on Moscow under the bipartisan Countering America's Adversaries Through Sanctions Act.
"We've given you the tools needed to meet this challenge. If you continue to leave those tools on the shelf, we will push for additional legislative action with more stringent requirements," according to the letter. "If you refuse to protect the United States from a hostile foreign government, Congress must act on our own. The future of our democracy is on the line."