The U.S. Ambassador to the United Nations told an emergency meeting of the Security Council on Friday that Washington was "fully justified" in striking a Syrian airfield overnight.
"The United States took a very measured step last night," Nikki Haley said, referring to the retaliatory missile strikes. "We are prepared to do more, but we hope that will not be necessary."
The U.S. said Bashar al-Assad's regime used the Shayrat airfield Tuesday to launch aircraft carrying poison gas that killed scores of civilians in the town of Khan Shaykhun in Idlib province.
"The United States will no longer wait for Assad to use chemical weapons without any consequences," Haley said. "Those days are over."
Haley said that the international community must now move to a new phase in Syria — a drive toward a political solution. She said until this point, Assad and his allies have not taken political negotiations seriously.
"We expect Russia and Iran to hold their ally accountable and abide by the terms of the cease-fire," she added.
Russia's deputy U.N. envoy was irate over the U.S. unilateral military strike, calling it a "flagrant violation of international law and an act of aggression."
"We strongly condemn the illegitimate actions by the U.S.," Vladimir Safronkov told council members. "The consequences of this for regional and international stability could be extremely serious."
He dismissed U.S. calls to move the political process forward, calling them "hypocritical" in the wake of the military strike.
"As we see it, you have chosen a different path," Safronkov said. "We must recall that when you take your own path, this leads to horrible tragedies for people in the region," he said, recalling the 2003 invasion of Iraq and the U.S. intervention in Libya in 2011 as part of a NATO coalition.
Syria's deputy U.N. envoy Mounzer Mounzer said the strike was illegal aggression.
"These aggressions really promise total chaos in many parts of the world and will make the law of the jungle the only way to deal with regional and economic crises," he said.
China, which normally votes with Russia in the council on matters relating to Syria, did not overtly criticize the U.S. strike, perhaps because President Xi Jinping is currently meeting with President Donald Trump in Florida. Instead, Ambassador Liu Jieyi called only for a political solution, saying, "military means will not work, they will only worsen the suffering of the Syrian people."
The emergency meeting was called by council member Bolivia. Ambassador Sacha Llorenti delivered an impassioned statement in the council denouncing the U.S. strike as a violation of international law, and an impediment to an impartial and independent investigation into the Khan Shaykhun chemical attack.
Many Western allies expressed support for the intervention, calling it an appropriate and measured response.
Ally Sweden did question its legality, saying such action must be based on international law.
"Last night's missile attack also raises questions of compatibility with international law," Ambassador Olof Skoog told council members.
Under international law, military action against another country requires either Security Council authorization or cause under Article 51 of the U.N. Charter, which says that states have an inherent right to individual or collective self-defense.