WASHINGTON (CBSNewYork/AP) — President Donald Trump has signed a bill to impose new sanctions on Russia, a White House official confirmed to CBS News.

The package of stiff financial sanctions against Russia passed Congress last week with overwhelming support. The bill also targets Iran and North Korea.

Vice President Mike Pence said the United States prefers a constructive relationship with Russia, but the president and Congress stand behind the message the sanctions send, CBS2’s Jessica Layton reported.

“A better relationship and the lifting of sanctions will require Russia to reverse the actions and conduct that caused sanctions to be imposed in the first place,” he said Wednesday.

Trump called the bill — which limits his ability to ease the sanctions — flawed, adding “as president, I can make far better deals with foreign countries than Congress.”

He said he signed the bill in the interest of national unity.

“The president favors tough measures to punish and deter the bad behavior of the rogue regimes in Iran and North Korea, and he also sent a clear signal we won’t tolerate interference in the Democratic Process by Russia,” White House Press Secretary Sarah Huckabee Sanders said.

Russia’s prime minster responded, calling the Trump administration “utterly powerless.”

Moscow also ordered a reduction in the number of U.S. diplomats in Russia.

(© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)