WASHINGTON -- US President Donald Trump's former chief strategist undermined his boss by saying there is no military solution to the nuclear standoff with North Korea, a Republican lawmaker has said.

Steve Bannon, a key architect of Trump's presidential campaign, left the White House on Friday.

In an interview that aired Sunday on New York's AM 970, Rep. Peter King (R-NY) said Bannon had become a part of the reason the White House "has just not been functioning."

He especially cited Bannon's recent interview with the American Prospect in which he rebuffed the president's threats of military action against North Korea.

"He was publicly disagreeing with the president's policy on North Korea," King said. "And this was the policy of President Trump, Secretary Mattis, Secretary Tillerson, and the chairman of the national security council Gen. McMaster. For him to go public and basically tell North Korea that we have no military option against them, that was undermining the president of the United States."

Bannon told the publication there's "no military solution (to North Korea's nuclear threats), forget it."

He also said, "Until somebody solves the part of the equation that shows me that 10 million people in Seoul don't die in the first 30 minutes from conventional weapons, I don't know what you're talking about. There's no military solution here. They got us."

Bannon went further to say he might consider an unlikely deal in which the US pulled out its troops from South Korea in exchange for Beijing stopping Pyongyang's nuclear buildup. (Yonhap)