President Donald Trump's decision to withdraw U.S. troops from Syria is "a great big Christmas gift" to Russian President Vladimir Putin and Ayatollah Khomeini of Iran, Sen. Chris Coons, D-Del., said Sunday.

In an interview on CBS News' "Face The Nation," Coons said the president moved too quickly — and without a "heads-up" to America's allies.

"By abruptly withdrawing from Syria, President Trump is handing a great big Christmas gift to Vladimir Putin of Russia and to Ayatollah Khomeini of Iran," he said, adding getting praise from Putin and Sen. Rand Paul, R-Ky., a foe of U.S. troop intervention overseas, is "a pretty good sign it's a terrible idea."

"The mission against ISIS where the United States built a coalition of dozens of countries is on the verge of winning, of completely shutting down ISIS in Syria," Coons said. "And for us to withdraw right now and abandon our Kurdish allies paves a highway for control of Syria for either Iran and Russia or Turkey – none of which is a good outcome – and profoundly disorients our allies who came into this fight alongside us and weren't consulted and weren't given enough of a heads-up."

Coons also warned against Trump nominating an "America First" proponent as new Secretary of Defense to succeed James Mattis.

"If the president instead chooses an 'America first' defense secretary, we will have confirmation hearings, we'll hopefully get the chance to ask him or her probing questions," he said. "But if it's someone who doesn't believe in the importance of our alliances as Secretary Mattis did – if this is someone who doesn't have a clear-eyed view of the very real threat to our security posed by both Russia and China, then they won't get my support and they won't enjoy this sort of broad bipartisan support that Secretary Mattis has for so long."

Coons also decried the "worst week for the American stock markets in a decade" — and urged the president not to criticize, or oust, Federal Reserve Chairman Jerome Powell.

"The independence of the Fed is a key linchpin of American economic security," he said. "And I just . . . plead with the president to reconsider what is a very dangerous course in economic policy."