The United States vowed Friday to keep the pressure on Syria after the intense nighttime wave of missile strikes from US ships, despite the prospect of escalating Russian ill will that could further inflame one of the world's most vexing conflicts. 

Standing firm, the Trump administration signaled new sanctions would soon follow the missile attack, and the Pentagon was even probing whether Russia itself was involved in the chemical weapons assault that compelled President Donald Trump to action. The attack against a Syrian air base was the first US assault against the government of President Bashar Assad.

Much of the international community rallied behind Trump's decision to fire the cruise missiles in reaction to this week's chemical weapons attack that killed dozens of men, women and children in Syria. But a spokesman for Russian President Vladimir Putin warned that the strikes dealt "a significant blow'' to relations between Moscow and Washington.

At the United Nations, Russia's deputy ambassador, Vladimir Safronkov, strongly criticized what he called the US "flagrant violation of international law and an act of aggression'' whose "consequences for regional and international security could be extremely serious." He called the Assad government a main force against terrorism and said it deserved the presumption of innocence in the chemical weapons attack. 

US officials blame Moscow for propping up Assad.

"The world is waiting for the Russian government to act responsibly in Syria," Nikki Haley, the US ambassador to the UN, said during an emergency Security Council session. "The world is waiting for Russia to reconsider its misplaced alliance with Bashar Assad."

Haley said the US was prepared to take further action in Syria but hoped it wouldn't be necessary.

In Florida with the president, meanwhile, Treasury Secretary Steven Mnuchin said: "We will be announcing additional sanctions on Syria as part of our ongoing effort to stop this type of activity and emphasize how significant we view this. We expect that those will continue to have an important effect on preventing people from doing business with them." (AP)