The White House said on Monday it is considering additional sanctions on Russia following a suspected poison gas attack in Syria, but has not made a decision yet, Reuters reported.

“We are considering additional sanctions on Russia and a decision will be made in the near future,” White House spokeswoman Sarah Sanders said in a statement.

She did not say why sanctions would be imposed but the U.S. ambassador to the United Nations, Nikki Haley, said on Sunday that the United States is preparing new sanctions on Russia over its support of Syrian President Bashar al-Assad.