UNITED NATIONS (AFP) - US ambassador Nikki Haley on Tuesday (April 17) shot back at a White House aide who suggested that "confusion" had led her to mistakenly announce fresh sanctions on Russia.

"With all due respect, I don't get confused," Ms Haley said in a statement to Fox News that was confirmed by the US mission to the United Nations.

Ms Haley on Sunday said new US sanctions on Russia would be announced on Monday by US Treasury Secretary Steve Mnuchin, but the White House said no such decision had been made.

President Donald Trump's assistant for economic policy, Mr Larry Kudlow, told reporters that Ms Haley "got ahead of the curve" with her announcement of sanctions on Russia over an alleged chemical attack by President Bashar al-Assad's forces in Syria.

"There might have been some momentary confusion about that," Mr Kudlow told reporters ahead of a meeting between Mr Trump and Japanese Prime Minister Shinzo Abe.

A former governor of South Carolina who has been a leading voice on foreign policy since taking over as US ambassador to the United Nations, Ms Haley has taken a hard line on Russia.