US vows to keep up pressure on Syria despite Russian displeasure over strikes
The United States has vowed to keep up the pressure on Syria after a wave of missile strikes despite the prospect of escalating Russian dissatisfaction that could further inflame the conflict.
The US signalled new sanctions would follow and the Pentagon was probing whether Russia was involved in the chemical weapons assault that compelled US 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 Mr Trump's decision in reaction to this week's chemical weapons attack that killed dozens of people in Syria.
But a spokesman for Russian president Vladimir Putin warned the strikes dealt "a significant blow" to relations between Moscow and Washington.
A key test comes next week when secretary of state Rex Tillerson becomes the first Trump Cabinet member to visit Russia.
Foreign Minister Boris Johnson had planned to visit Russia this week but decided to cancel the trip because of fast-moving events in Syria.
At the United Nations on Friday, Russia's deputy ambassador Vladimir Safronkov strongly criticized what he called the US "flagrant violation of international law and an act of aggression".
He said its "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 over the chemical weapons attack.
The US ambassador to the UN, Nikki Haley, said the world is waiting for the Russian government "to act responsibly in Syria" and "reconsider its misplaced alliance with Bashar Assad".
Speaking during an emergency Security Council session, she said the US was prepared to take further action in Syria but hoped it would not be necessary.
In Florida with the president, treasury secretary Steven Mnuchin said additional economic sanctions on Syria were being prepared.
Thursday night's strikes - some 60 cruise missiles fired from two ships in the Mediterranean - were the culmination of a rapid, three-day transformation for Mr Trump.
He has long opposed deeper US involvement in Syria's civil war but advisers said he was outraged by images of young children among dozens killed in the chemical attack.
The decision undercut another campaign promise for Mr Trump: his pledge to try to warm relations with Moscow.
After months of allegations of ties between his election campaign and the Kremlin - the subject of congressional and FBI investigations - Mr Trump has found himself clashing with Mr Putin.
On Friday, senior US military officials were looking more closely at possible Russian involvement in the poison attack.
Officials said a drone belonging to either Russia or Syria was seen hovering over the site after the assault earlier this week.
It returned late in the day as citizens were going to a nearby hospital for treatment. Shortly afterwards, officials say the hospital was targeted.
The officials said they believe the hospital attack may have been an effort to cover up evidence of the earlier assault.
White House officials caution that Mr Trump is not preparing to plunge the US deeper into Syria.
Spokesman Sean Spicer said the missile attack sent a clear message to Assad, but he avoided explicitly calling for the Syrian to leave office.
The impact of the strikes was also unclear. Despite intense international pressure, Assad has clung to power since a civil war broke out six years ago, helped by financial and military support from Russia and Iran.
Russian military personnel and aircraft are embedded with Syria's, and Iranian troops and paramilitary forces are also on the ground helping Assad fight opposition groups hoping to topple him.