Indian-American Democratic Congressman Ro Khanna, a fierce critic of Donald Trump, has come out in support of the President's decision to pullout US troops from Syria and Afghanistan, saying his party colleagues should not pile on without offering an alternative vision.

The 42-year-old Congressman, who represents Silicon valley, has surprised many by coming out in strong support of president's decision to withdraw American troops from Syria and his reported plans to bring back nearly half of the 15,000 of his troops from war-ravaged Afghanistan.

Khanna said that he is doing so in the national interest.

"A few days ago, I was with Trump as he signed one of my bills. I said Mr President, China has not been in a war since 1979. If we want to win the race against them, we should not get bogged down in war. He nodded and then observed that they have enriched themselves without firing a shot," Khanna wrote in an op-ed published in The Washington Post.

Khanna, who is on the Armed Services Committee, was re-elected for the second term in the November mid-term elections.

"President Trump is receiving an onslaught of criticism for his decision to withdraw troops from Syria and Afghanistan. Congressional Democrats should not pile on without offering an alternative vision," he wrote.

He said that though the president's desire on troops withdrawal should be applauded, but he should be challenged to assemble a team that does so with better planning.

"We should applaud the president's desire to put an end to these interventions, but should challenge him to assemble a team that does so with better planning and diplomacy. We should articulate a foreign policy doctrine of responsible withdrawal that prioritises restraint and human rights," he said.

Khanna said that Trump's instincts as a candidate of ending the war and bringing troops home were spot-on.

"There should be a short timeline for bringing home our troops to allow for a smooth transition. We should engage in direct talks with the Taliban and seek a negotiated settlement, involving regional actors such as Pakistan, Iran, Russia, China and India," Khanna said.

However, his open support and praise of Trump has angered his own party colleagues.

The entire Democratic leadership has rallied behind the outgoing Defence Secretary James Mattis for his opposition to Trump's move on Syria and Afghanistan.

The decision to withdraw troops from Afghanistan has not been officially announced yet.

"The genuinely anti-war & left-wing member of Congress, Khanna, has been idiotically & hilariously attacked as a "Trump apologist" because he praised Trump's desired withdrawal of troops from Syria & Afghanistan," tweeted Intercept Journalist Glenn Greenwald.