WASHINGTON, March 6 (Xinhua) -- White House National Economic Council Director Gary Cohn said on Tuesday that he was resigning, as President Donald Trump's administration prepares to impose tariffs on imported steel and aluminum.

Cohn, a veteran Wall Street banker, has served as Trump's chief economic advisor since the beginning of the administration.

"It has been an honor to serve my country and enact pro-growth economic policies to benefit the American people, in particular the passage of historic tax reform," Cohn said in a statement released by the White House.

Cohn struck an early rapport with Trump, and played an important role in forging the tax cut bill, which was signed into law by Trump last December.

Trump announced on March 1 that his administration planned to impose a 25-percent tariff on steel imports and a 10-percent one on aluminum, as these imports threaten U.S. national security.

Cohn, a "globalist" within the White House, has been mounting a last-ditch attempt to head off Trump's new tariff plan on steel and aluminum. He has summoned executives from U.S. companies that depend on aluminum and steel to meet with Trump.

Trump, however, reiterated his commitment to slapping tariffs on steel and aluminum on Tuesday.

"When we're behind on every single country, trade wars aren't so bad," Trump said. "The trade war hurts them, not us."

Trump's new tariff plan was based on an investigation conducted by the U.S. Commerce Department. Cohn told his colleagues that the investigation report was "terrible" because it did not properly analyze the jobs that would be lost in downstream industries, the U.S. news outlet Axios reported.

"Gary Cohn deserves credit for serving his country in a first class way. I'm sure I join many others who are disappointed to see him leave," Lloyd Blankfein, chairman and chief executive of Goldman Sachs and Cohn's former boss, tweeted.