Immediate action is needed to protect the Syrian people but it should be "rooted in the principles of the United Nations and international law," UN political affairs chief Jeffrey Feltman said on Friday.

"There can be no genuine protection if the parties to the conflict, government and opposition alike, are permitted to act with impunity and if the Syrian government continues to commit human rights violations against its own citizens," he told the U.N. Security Council.

U.S. cruise missile strikes on a Syrian air base were one step away from clashing with the Russian military, Russian Prime Minister Dmitry Medvedev charged on Friday, underscoring the risks in U.S. President Donald Trump's first major foray into the Syrian civil war.