The White House is weighing new sanctions against Russia "in the near future" over Moscow's support for Syria's suspected chemical attack on a Damascus suburb that activists claim killed at least 40 people.
"We are considering additional sanctions on Russia and a decision will be made in the near future," White House press secretary Sarah Huckabee Sanders said Monday.
Nikki Haley, the U.S. ambassador to the United Nations, had said Sunday on CBS's Face the Nation that details of fresh economic sanctions would be announced on Monday.
There was no explanation for the apparent delay.
Earlier, Syrian state media broadcast what it said were images of hundreds of Syrians celebrating their government's successful interception of most of the missiles launched into Syria early Saturday by the United States, Britain and France.
The rally in Omayyad Square in Syria's capital Damascus was described on state TV as a "salute to the achievements of the Arab Syrian Army." It featured crowds waving flags, fireworks and celebratory gunfire.
The event also commemorated "Evacuation Day," Syria's national holiday to mark the final withdrawal of French occupation forces from the country in 1946.
Britain, France and the United States said they bombed sites linked to Syria's chemical weapons program after the suspected attack in Douma, just outside of Damascus.
Syria and its ally Russia have sought to downplay the impact of the strikes, saying Syrian air defenses shot most of them down. The Pentagon said none of its aircraft or missiles were hit by Syrian air defenses.
Syria and Russia have also denied that any chemical attack took place, and so far there has been no independent confirmation of civilian casualties.
In Britain, Prime Minister Theresa May told British lawmakers Monday that Syria, supported by Russia, was trying to conceal facts about the attack.
May was taking questions in Parliament about her decision to authorize the joint strikes.
She said there was "clear evidence" Syria was behind the chemical attack. "No other group could have carried this out," May said.
British medical and scientific experts analyzed reports, images and video footage from the incident and concluded the victims were exposed to a toxic chemical, she said.
Her comments follow allegations by the head of an international chemical weapons watchdog on Monday that Syrian and Russian officials cited "pending security issues" to keep independent inspectors from reaching the site of the suspected April 7 chemical attack.
Ahmet Uzumcu, the director-general of the Organization for the Prohibition of Chemical Weapons, told a meeting of the group's executive council in the Hague on Monday that his team has not yet deployed to Douma two days after arriving in Syria.