The United States took a very measured step that was "fully justified" when it fired missiles at a Syrian air field over a deadly toxic gas attack, says UN Ambassador Nikki Haley.
"We are prepared to do more, but we hope that will not be necessary," she told the UN Security Council.
"The United States will not stand by when chemical weapons are used. It is in our vital national security interest to prevent the spread and use of chemical weapons."
UN Secretary General Antonio Guterres appealed to parties involved in the Syrian conflict for restraint to avoid adding to the suffering of Syria's people.
"Mindful of the risk of escalation, I appeal for restraint to avoid any acts that could deepen the suffering of the Syrian people," he said in a statement, after US President Donald Trump ordered missile strikes against a Syrian airfield from which a deadly chemical weapons attack was launched.
Russia's deputy UN envoy, Vladimir Safronkov, condemned the "illegitimate" US strikes in Syria and said the consequences for regional and international stability could be extremely serious.
He described them as an "attempt to distract attention from the many victims amongst the peaceful population in Iraq and Syria caused by unilateral actions".
But US allies took a different stance.
Syrian President Bashar al-Assad's goal is "annihilation, quite simply, of all those who resist him, whatever the price might be," French UN Ambassador Francois Delattre says.
He told the UN Security Council that the US strikes over a deadly toxic gas attack as legitimate as it had become "essential to deter" Assad.
Assad has been "put on notice" by the US Britain's UN Ambassador Matthew Rycroft said on Friday, describing it as a "proportionate response to unspeakable acts".
"Without Russia's seven vetoes in the Security Council, defying the views of other members of this council, Assad would not have faced sanctions and justice," Rycroft told the 15-member council.
