The UN Security Council met in an emergency session on Friday following the US missile strikes in Syria, with France and Britain voicing support for Washington's military response to a suspected chemical weapons attack.
France and Britain called for a renewed push for political negotiations to end the six-year war in Syria.
"The United Kingdom fully supports the United States' action overnight, which was an appropriate response to such a heinous crime, a war crime," British Ambassador Matthew Rycroft said as he headed into the meeting.
US President Donald Trump on Thursday ordered cruise missile strikes on a Syrian air base in response to a suspected chemical attack on a rebel-held town that killed 86 people and shocked the world.
The strike -- the first direct US action against President Bashar al-Assad and Trump's biggest military decision since taking office -- marked a dramatic escalation in American involvement in Syria's six-year war.
Describing the US strikes as "appropriate," French Ambassador Francois Delattre expressed hope the US action would be a "game changer and help boost the political negotiations."
The council meeting was called by Bolivia, which branded the US strikes a violation of international law.
Bolivian Ambassador Sacha Lorenti said the United States had behaved like "investigator, attorney, judge and executioner" in Syria.
"This is not what international law is all about," he told reporters ahead of the meeting.
Russia angrily denounced the military action as an "aggression against a sovereign state."
- Push for political talks -
UN Secretary General Antonio Guterres urged restraint and a renewed push for peace in Syria, saying in a statement that "there is no other way to solve the conflict than through a political solution."
"It is it is time now to focus on the political process," Rycroft echoed.
Eighty-six people including at least 27 children died in the suspected attack in Khan Sheikhun. Results from post-mortems performed on victims point to exposure to the deadly sarin nerve agent, according to Turkish health officials.
Guterres called on the council to unite and agree on a way forward on Syria.
"For too long, international law has been ignored in the Syrian conflict, and it is our shared duty to uphold international standards of humanity," he said.
"This is a prerequisite to ending the unrelenting suffering of the people of Syria."
The Security Council failed during a meeting Thursday to agree on terms for an investigation of the suspected sarin gas attack in Khan Sheikhun.
Russia's Deputy Ambassador Vladimir Safronkov on Thursday warned of "negative consequences" from the US military action, which he described as a "doubtful, tragic enterprise."
"Look at Iraq, look at Libya," he said, referring to Western interventions that unleashed years of chaos in those countries.