Russian efforts to veto United Nations action against Syria left US, British and French allies no option but to launch airstrikes against key installations, North Atlantic Treaty Organisation chief Jens Stoltenberg said.
In a "combined operation" on Friday night, the UK, US and France launched airstrikes in response to a suspected chemical weapons attack that left up to 75 dead in Douma last week.
Both Iran and Russian Federation, who back Syrian dictator Bashar al-Assad, blasted the attacks, which Downing Street said "had been a success".
Despite sustained diplomatic efforts, the Syrian regime continues to use chemical weapons against its own people.
No "final decision" yet on Syria response, White House says
It was not clear whether the presence of the investigators could affect the timing of any US military action. Trump said. "The nations of the world can be judged by the friends they keep".
Russia's Foreign Ministry says the attack was an attempt to derail an investigation into a purported chemical attack.
He added, "But since this was blocked by Russian Federation, there was no other alternative".
"I support the actions taken by the United States, the United Kingdom and France".
Members of the MA congressional delegation criticized President Trump for taking military action without congressional approval and called on him to explain the USA strategy in Syria. They also made clear that their military action was limited to the Syrian regime's facilities enabling the production and employment of chemical weapons. "The use of chemical weapons is unacceptable, and those responsible must be held accountable", Stoltenberg said.