UN Ambassador Nikki Haley
US President Donald Trump today put the brakes on a preliminary plan to impose additional economic sanctions on Russia, walking back an announcement yesterday by US Ambassador to the United Nations Nikki Haley that the Kremlin had swiftly denounced as "international economic raiding."

Preparations to punish Russia anew for its support of Syrian President Bashar al-Assad's Government over the alleged chemical weapons attack in Syria caused consternation at the White House.

Haley told CBS News that sanctions on Russian companies behind the equipment related to Assad's alleged chemical weapons attack would be announced today by Treasury Secretary Steven Mnuchin.

But as officials in Moscow condemned the planned sanctions as overly punitive, Trump conferred with his national security advisers and told them he was upset the sanctions were being officially rolled out because he was not yet comfortable in executing them, according to several people familiar with the plan.

Administration officials said the economic sanctions were under serious consideration, along with other measures that could be taken against Russia, but said Trump had not given final authorisation to implement them.

Administration officials said today it was unlikely Trump would approve any additional sanctions without another triggering event by Russia, describing the strategy as being in a holding pattern.

Sometime after Haley's comments on CBS, the Trump Administration notified the Russian Embassy in Washington that the sanctions were not in fact coming, a Russian Foreign Ministry official said.

The Trump team decided to publicly characterise Haley's announcement as a misstatement. White House press secretary Sarah Huckabee Sanders said in a statement today: "We are considering additional sanctions on Russia and a decision will be made in the near future."

Privately, another White House official said Haley got ahead of herself and made "an error that needs to be mopped up."

But other Administration officials expressed scepticism that Haley had merely misspoken. They said Haley is one of the most disciplined and cautious members of the Cabinet, especially when it comes to her public appearances. She regularly checks in with Trump personally to go over her planned statements before she sits for television interviews.